Utran description-3-days (1)
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  • 1. Introduction <br /> 1.1 Context <br /> 1.2 Standardization <br /> 1.3 UMTS goals <br /> 1.4 UMTS technical overview <br /> 2. Services Provided <br /> 2.1 UMTS services principles <br /> 2.2 UMTS bearer services <br /> 2.3 Tele-services <br /> 2.4 UMTS terminals <br /> 3. UMTS system description <br /> 3.1 Logical Architecture <br /> 3.2 Protocol Architecture <br /> 3.3 Call scenario <br /> 4. WCDMA for UMTS <br /> 4.1 Context <br /> 4.2 Spread spectrum modulation <br /> 4.3 Code Division Multiple Access (CDMA) <br /> 4.4 Rake receiver <br /> 4.5 Power control <br /> 4.6 Soft Handover <br /> 4.7 Typical coverage and capacity values <br />
  • Will explain “3rd generation”-->1.1 Historical <br /> Will explain “IMT-2000 defined by ITU”-->1.2 Standardization <br /> The UMTS Forum is an international and independent body, uniquely committed through the building of cross-industry consensus to the successful introduction and development of UMTS/IMT-2000 ’’third generation’’ mobile communications systems <br /> www.umts-forum.org <br />
  • Congestion <br /> more than 300 million wireless subscribers worldwide -->booming market -->congestion of 2G (Japan case )-->need to increase system capacity <br /> Limited mobility around the world <br /> great amount of 2G systems not compatible with each other-->need for a global standardisation <br /> Limited offer of services <br /> more than 200 million internet users  communications are not limited to speech anymore  2G are too limited to offer data services (low bit rate, circuit switching)  Need for new multimedia services and applications (video telephony, e-commerce...) <br />
  • Note: Alcatel will skip HSCSD! <br />
  • EDGE mainly concerns the modulation scheme on the GSM timeslots. The modulation technique that GSM uses is called Gaussian Minimum Shift Keying (GMSK). With GMSK, one bit per symbol can be transmitted (21=2 phase states). EDGE will extend these boundaries by applying a new alternative modulation technique, that is 8 Phase Shift Keying. 8PSK provides for the transmission of 3 bits per symbol (23 phase states) , that is three times the transmission rate of GMSK. <br />
  • In these examples, the useful rate is supposed to be : <br /> 9.6 Kbps for GSM <br /> 50 Kbps for GPRS <br /> 150 Kbps for EDGE <br /> 2 Mbps for UMTS <br /> same examples with different rates for GPRS : <br /> Downloading a Map: 13 s with GPRS CS-2 and 3 Time Slots (~30Kbps) <br /> Downloading a Word Document: 135 s with GPRS CS-2 and 3 Time Slots <br />
  • *A recommendation is not a specification. <br /> IMT-2000: International Mobile Telecommunications-2000 <br /> ITU:International Telecommunication Union (www.itu.int) <br /> Problem: <br /> 2GHz is already used by 2G systems in US : shall the frequency carriers of 2G be reframed? Isn’t EDGE the most suitable technology for 3G systems? <br />
  • ITU is an international organisation composed of members of governments all over the world. <br /> ETSI, ARIB, TIA… are regional standardization bodies composed of companies such as manufacturers and operators. <br /> IMT-2000 is a result of the collaboration between the ITU and several regional standardization bodies, which are located mainly in Europe, in Japan and in the US <br /> In the first phase of 3rd generation standardization, each region carried out its own standardization process to meet the IMT-2000 requirements but also to take into account its own 2nd generation mobile systems. <br /> As similar technologies were being standardized in several regions around the world, initiatives were made to create a single forum for WCDMA standardization for a common WCDMA specification, e.g 3GPP (Third Generation Project Partnership), 3GPP2 <br /> Each Consortium has proposed one or more Radio Interfaces for IMT-2000, which have been approved for ITU. UMTS contains the two interfaces standardized by 3GPP: IMT-DS and IMT-TC. <br />
  • Which radio technologies belong to UMTS? <br /> UMTS contains the two interfaces standardized by 3GPP: IMT-DS also called UMTS FDD and IMT-TC also called UMTS TDD. UMTS core network is the evolved GSM network. <br /> Different regions of the world will adopt different radio interface technologies according to the existing 2G system. <br /> The connection of these different radio technologies to different core networks will require cooperation between the current standardization bodies. UMTS Release 99 does not contain these options. <br /> ERAN: EDGE Radio Access Network <br />
  • Note: CDMA in yellow is cdmaOne (IS-95) <br /> Market share between digital systems <br /> GSM = 48% <br /> CDMA = 28% <br /> TDMA = 15% <br /> PDC = 9% <br /> Western Europe:GSM = 100% <br /> US & Canada:GSM = 12%CDMA = 49% TDMA = 39% <br /> China:GSM = 87%CDMA = 13% <br /> Japan:CDMA = 36% PDC = 64% <br /> RoW:GSM = 41%CDMA = 35% TDMA= 24% <br /> For information: <br /> 1999 total market (including analog systems): 41.8 B$ <br /> (US & Canada = 8.9 B$ Western Europe = 8.8 B$ China = 4.8 B$ Japan = 4.6 B$) <br />
  • What about Global Roaming? <br /> ITU leads this process of harmonizing, which is necessary for a global terminal roaming and to offer operators some degree of flexibility in selecting their 3rd generation technology. <br /> However because of different radio technologies global roaming will continue to require specific arrangements between operators, such as multi-mode and multi-band handsets and roaming gateways between the different core networks. <br /> We can also imagine a compatibility of SIM cards instead of multi-mode handsets (ie using a UMTS SIM card in a CDMA2000 terminal) <br /> In fact, Global Roaming is not the issue : <br /> The challenge is roaming and seamless services across boarders of heterogeneous private and public, fixed and mobile access networks rather than Global Roaming. <br />
  • 3GPP is a joint organization of standardization bodies of Europe, Japan and US <br /> To meet new market requirements, 3GPP specifications are continually being enhanced with new features. In order to provide developers with a stable platform for implementation while at the same time allowing the addition of new features, the 3GPP uses a system of parallel "releases”: release 99, release 4, release 5, ... <br /> R99, The first Release of the 3rd generation specifications was essentially a consolidation of the underlying GSM specifications and the development of the new radio access network. The foundations were laid for future high-speed traffic transfer in both circuit switched and packet switched modes. <br /> R99 is based on ATM transmission technology architecture through the RAN towards CN <br />
  • 3GPP is large organization, which was created in 1998. <br /> Detailed technical work is carried out in 5 Technical Specification Groups (TSG) divided into subgroups. <br /> Many people are involved: it is estimated that more than one thousand people contribute in one way or another. This is an unprecedented number of experts working on the same project. <br /> 3GPP has delivered almost stable specifications, accepted by the majority of major industrial players, in only two years. <br />
  • For information <br /> NB : the TS 21.101 lists the existing Technical Specifications for the release R 99. <br /> NB : the TS 21.102 lists the existing Technical Specifications for the release R 4. <br /> NB : the TS 21.103 lists the existing Technical Specifications for the release R 5. <br />
  • GPRS implementation: <br /> TMN: November 2000: 1st European operator <br /> Telering:January 2001 <br /> UMTS: <br /> field trials starting from end 2001 <br /> EDGE <br /> HSDS (High Speed Data Service) is available with Evolium™ BSS in B8 release for E-GPRS <br />
  • High quality <br /> Voice (enhancement compared to GSM) <br /> Data (multimedia) <br /> Convergence <br /> Fixed and mobile networks <br /> Data and telecommunication networks (mobile phone and computer may merge) <br /> Services <br /> New, personalized, ubiquitous (but yet to be invented!) <br /> Depend on the location <br /> countryside and big cities <br /> high bit rate services will be offered when standing close to the base station <br /> Depend on the terminal <br /> different classes of terminals according to the services the user will have <br />
  • To access services from everywhere in the world, <br /> but radio interfaces should be adapted to the environment <br /> 2 Mbps small cells (due to interference level) <br /> 144 kbps large cells <br /> Transmission in TDD is discontinuous. This implies a reduced average transmission power and leads to smaller cells for TDD (pico and micro). <br /> What about UMTS deployment? <br /> UMTS will be compatible with GSM networks (Handover between the two systems should be applied) <br /> There will be UMTS islands in a sea of GSM (at least at the beginning) <br /> What about the satellite component? <br /> The MSS (Mobile Satellite Service) is also called Satellite Component. <br /> It aims to fill the gap coverage, especially maritime coverage, and to provide global roaming (niche market of global roamers) <br /> But it cannot penetrate the core of modern buildings. <br /> It is likely to come by 2007. <br />
  • It is the same well-known architecture as the 2nd generation mobile system, but <br />  Reconfiguration of the AN, or changes in the AN domain functionality shall have minimal impact on Core Network functions, and vice-versa. <br />  A given Access Network (e.g., the UTRAN) may provide access to different type of Core Networks via the Iu reference point and vice versa (UTRAN, BRAN, Satellite) <br /> That’s why we speak about Iu reference point, not about Iu interface (an interface differs from a reference point in that an interface is defined where specific information is exchanged and needs to be fully recognised) <br /> In the following material we will not speak about MSS and BRAN, only about UTRAN. <br />
  • FDD (Frequency Division Duplex): use of DS-CDMA (or W-CDMA) <br /> Frequency Bands1920/1980 MHz (UL) / 2110/2170 MHz (DL): Region 1 <br /> Channel Spacing5 MHz <br /> Channel Raster200 kHz <br /> Carrier chip rate3.84 Mchip/s <br /> Radio Frame length10 ms with 15 TS <br /> FEC codesConvolutional codes, Turbo-codes <br /> ModulationQPSK <br /> Bearer Capabilityup to 2 Mbps <br /> Inter RNS synchronot needed <br /> TDD (Time Division Duplex): use of TD-CDMA <br /> Frequency Band1900/1920 MHz and 2010/2025 MHz (UL&DL) <br /> Idem FDD <br /> Inter RNS synchroneeded <br /> The variable rates are achieved by the used of codes (& multi-slot allocation for the specific case of TDD) <br /> FDD (Frequency Division Duplex) shall provides a continuous 3G coverage. <br /> TDD (Time Division Duplex) mode provides specific solutions for asymmetric traffic and dedicated indoor systems, in line with the market requirements <br /> In the following material we will focus on UMTS FDD <br /> Note : FEC = Forward Error Correction <br />
  • The FDD band is split into 6 licenses in Germany, into 4 in France. <br /> MSS not allocated yet. <br /> No band guards between operators and between TDD and FDD: <br /> it may cause problems! <br /> Need for cooperation between operators <br />
  • Solution: <br /> A: 1-F; 2-T; 3-T; 4-F; 5-T <br /> B: 1-T; 2-T; 3-T; 4-T <br />
  • Solution: <br /> C: 1-F; 2-T; 3-T; 4-T; 5-T <br /> D: 1 <br /> E: 3 <br /> F: 1-T; 2-F; 3-F; 4-T <br />
  • Basic telecommunication services are divided in two broad categories: <br /> - bearer services: provide the capability of transmission of signals between access points. They are related to lower layers. <br /> - tele-services: provide the complete capability, including terminal equipment functions, for communication between users. They are related to higher layers. <br /> Examples: <br /> - Bearer services: transmission at 9,6 kbps with a max BER of 10-3. This service can not be used alone, it needs protocols of upper layers to be controlled and relayed. <br /> -Tele-services: file transfer (the bit rate transfer depends not only on the bearer service but also on the application) <br /> See 3GPP23.107 <br />
  • Whereas 2G mobile systems offer mainly speech services (the content is provided by the user), UMTS has to support a wide range of applications with different quality of services. <br /> New Services: we can also imagine that the customer himself will be able to create its own new services (easy access ways to create services) <br /> UMTS bearer services shall provide the necessary capabilities to support multimedia services and to enable the user of a single terminal to establish and maintain several connections simultaneously. <br /> 3GPP shall standardise service capabilities (bearer services) and not the services (teleservices) themselves. <br />
  • Existing systems have largely standardised the complete sets of tele-services, applications and supplementary services which they provide. As a consequence, substantial re-engineering is often required to enable new services to be provided. In addition, the market for services is largely determined by operators and standardization. This makes it more difficult for operators to differentiate their services. <br /> This is the reason why tele-services should not be standardized : to motivate competition between new actors of the telecommunication market, i.e content providers. <br /> Today, it is hardly possible to predict the nature and the usage of most applications, as UMTS ought to be generic by nature to allow good support of existing applications and to ease the evolution of new applications. <br />
  • The VHE is defined as a system concept for personalized service portability across network boundaries and between terminals. <br /> The exact configuration available to the user at any instant will be dependent upon the capabilities of the USIM, terminal equipment and network currently being used, on behalf of subscription restrictions. <br /> The VHE can be considered as a distributed user profile, owned by the service provider, distributed at any moment between the terminal equipment, the USIM, the network operator and the service provider. <br /> A user can reasonably expect the service to be the same in any network (home and visited). In fact this is not likely to be the case:- emergency numbers change from one country to another- announcements are preferably made in the local language- value-added services, such as traffic news, are not localized, but refer back to the home area <br /> The VHE is the framework for configuring the state of the terminal and the services accessible to it. <br /> The Personal Service Environment describes how the user wishes to manage and interact with its communications services. The PSE is a combination of a list of subscriptions (detailing provisioned services), preferences associated with those services, terminal interface preferences and other information related to the user&apos;s experience of the system. Within the PSE the user can manage multiple subscriptions e.g. both business and personal, multiple terminal types and express location and temporal preferences. The Personal Service Environment is defined in terms of one or more User Profiles. <br /> See 3GPP 22.121 <br />
  • VHE defines Service Capability Servers and standardises the features. <br /> Services capabilities: <br /> Service capabilities are based on functionality and mechanisms /toolkits such as provided by SAT, MExE, IN and CAMEL. These service capabilities can be made visible to the applications through an application interface. <br /> Service Capability Servers: <br /> GSM/GPRS/UMTS bearer services: they offer mechanisms for applications to access basic bearer capabilities. <br /> MExE (Mobile Execution Environment) servers: Value added services are offered through a client/server relationship between the MExE server in the network and the Mobile Execution Environment (e.g. Java Virtual Machine or WAP browser) in the terminal (TS 22.057) <br /> SAT (SIM Application Toolkit) servers: mechanisms that offer additional capabilities to the communication protocol between smart card and mobile station (TS 22.004) <br /> CAMEL (Customised Application for Mobile networks Enhanced Logic) servers: CAMEL extends the scope of IN services provisioned to the mobile environment (TS 23.078) <br /> Service Capability Features <br /> Functionality offered by service capabilities that are accessible via the standardised application interface. Examples: Call Control, Location/Positioning, PLMN Information & Notifications <br /> Bearer Services: <br /> The service characteristics as they apply at a given reference point where the user accesses the bearer service. <br />
  • Other examples of (tele)services built from service capabilities features: <br /> Call Barring : to prevent outgoing calls to certain sets of destinations, based on the number dialled and on a wider range of parameters (time of day, day of week, location, roaming, type of call requested, cost of the service and/or destination). <br /> Call Filtering/Forwarding: this service allows the control of whether incoming calls are accepted, forwarded or terminated <br /> Hold: this service allows an established call to be maintained, whilst suspending use of the bearer from the incoming access point of the network. This saves on both air interface and network traffic resources when a call is temporarily suspended. <br /> Transfer: this service allows either an established or held call to be redirected to another destination. <br /> Call-back When Free: this service allows to be informed when the destination is next able to accept the call, allowing a new call to be originated. <br /> See 3GPP 22.105 (Annex A) <br />
  • See 3GPP TS 22.105 <br /> QoS: Quality of Service <br /> PS and CS domains provide a specific set of bearer capabilities. <br />
  • The bit rate target have been specified according to the Integrated Services Digital Network (ISDN): <br /> - the 144 Kbps data rate provides the ISDN 2B+D channel <br /> - the 384 Kbps provides the ISDN H0 Channel <br /> - the 1920 Kbps provides the ISDN H12 Channel <br /> (even though 2Mbps is generally used as the upper limit for IMT-2000 services, the exact service is specified to be 1.92 or 2.048 Mbps) <br /> Several backward compatibility requirements influence the technology applied to 3G systems. <br /> See 3GPP TS 22.105 <br />
  • Teleservices provide the full capabilities for communications by means of terminal equipment, network functions and possibly functions provided by dedicated centres. <br /> Multimedia teleservices support the transfer of several types of information. <br /> M-commerce : <br /> Non-physical = electronic goods (e-banking, e-flight ticketing, ...) <br /> Physical = electronic payment of physical goods (food, supplies, hardware, ...) <br />
  • Conversational (real time user to user) <br /> Adaptive Multi-Rate (AMR) speech service (see “Appendix” for more details): <br /> a multi-rate speech coder is used with 8 source rates: 12.2 (GSM-EFR), 10.2, 7.95, 7.40 (IS-41), 6.70 (PDC-EFR), 5.90, 5.15 and 4.75 Kbps.The AMR bit rates are controlled by the radio access network and do not depend on the voice activity. The AMR coder is able to switch its bit rate every 20ms. <br /> Video telephony (H324, H323, IETF multimedia architecture) <br /> H324 (originally specified for PSTN) should be used for video in CS connections <br /> H323 and IETF architecture (IETF SIP Session Initiation Protocol) are candidates for PS connections. <br /> Streaming (real time user to server) <br /> the data transfer has to be processed as a continuous stream. With streaming the browser can start displaying the data before the entire file has been transmitted These applications are typically unidirectional. <br /> Interactive (non real time user to server with delay requirements) <br /> Web browsing <br /> location based services <br /> computer games (sometimes classified as conversational class due to end-to end delay) <br /> Background (non real time user to server with fewer delay requirements, from a few seconds to a few minutes): <br /> e-mail delivery <br /> Short Message Service (SMS) <br /> Real-time services have higher priority than non-real time services. <br /> See 3GPP 23.107 <br />
  • Conversational speech <br /> Audio transfer delay requirements depends on the level of interactivity of the end users. To preclude difficulties related to the dynamics of voice communications, ITU-T Recommendation G.114 recommends the following general limits for one-way transmission time (assuming echo control already taken care of): <br /> 0 to 150 mspreferred range <br /> 150 to 400 msacceptable range (but with quality decreasing) <br /> above 400 msunacceptable range <br /> Interactive games <br /> Requirements for interactive games are obviously very dependent on the specific game, but it is clear that demanding applications will require very short delays, and a value of 250 ms is proposed, consistent with demanding interactive applications. <br /> Web-browsing <br /> In this category we will refer to retrieving and viewing the HTML component of a Web page, other components like images, audio/video clips are related to separate QoS Classes. From the user point of view, the main performance factor is how fast a page appears after it has been requested. A value of 2-4 seconds per page is proposed, however improvement on these figures to a target figure of 0.5 seconds would be desirable. <br /> Delay values represent one -way delay (i.e. from originating entity to terminating entity). <br /> See 3GPP TS 22.105 Annex B <br />
  • From 3GPP TS 22.115 <br />
  • At the moment UMTS specifies that it will provide location information to an accuracy of 50m. Different positioning methods are specified in R’99 such as: <br /> the cell coverage-based positioning method <br /> Observed Time Difference Of Arrival-Idle Period Down-Link (OTDOA-IPDL) <br /> network-assisted GPS methods <br /> 3GPP TS 22.071, TS 24.030 <br />
  • Functionally speaking, the User Equipment (UE) is composed of the Mobile Equipment (ME) and the UMTS Subscriber Identity Module (USIM). <br /> The Role of USIM is very similar to that of the SIM in GSM: <br /> - it is used to store subscriber identity, subscription data, authentication and ciphering keys, authentication algorithms <br /> - its security is improved compared to GSM with a mutual authentication between the card and the network. <br /> The interface between ME and USIM is the Cu interface, the importance of which is crucial for compatibility: even if full multi-mode Terminals will not be developed (in a first period at least), USIM-roaming will allow the subscriber to use different IMT2000 terminals with the same card. <br /> The UICC (UMTS integrated Circuit Card) is similar to SIM card in GSM with the same size (either ISO or plug-in).It may contain one or several USIM for different applications and also the SIM module in order to be used in a GSM terminal .Another possibility is to include additional mechanisms in the USIM part in order to provide the GSM access and be usable in a multi-mode UMTS/GSM terminal. <br /> TS 21.111: USIM and IC card requirements <br />
  • Bluetooth (See http://www.bluetooth.com) <br /> The idea was born in 1994. Ericsson initiated a study to investigate the feasibility of a low-power, low-cost radio interface between mobile phones and their accessories. The aim was to eliminate cables between mobile phones and PC cards, headsets and desk top devices… In February 1998, 5 companies (Ericsson, Nokia, IBM, Toshiba and Intel) ventured into a Special Interest Group (SIG) <br /> The Bluetooth system is operating in the 2.4 GHz ISM (Industrial Scientific Medicine) band. In a vast majority of countries around the world the range of this frequency band is 2400 - 2483.5 MHz. The equipment is classified into 3 power classes (class1 = 100mW=20dBm, class 2 = 2.5 mW=4dBm, class 3 = 1mW=0dBm <br /> WAP (Wireless Application Protocol) <br /> WAP is a technology designed to provide users of mobile terminals with rapid and efficient access to the Internet. <br /> Today, most people access the Internet from a desktop or home PC, which has a large screen and comprehensive keyboard. The mobile phone, on the other hand, has limited display capabilities and a simple keyboard. WAP helps overcome these limitations. A special "micro browser" takes the information from the Web and pares it down so that only the key information required by the user is displayed. <br />
  • Solution: <br /> A: 1-T; 2-T; 3-F <br /> B: 1-T; 2-T; 3-T; 4-F <br />
  • Solution: <br /> C: 1-F; 2-F; 3-F; 4-T; 5-T <br /> D: 1-F; 2-T; 3-T <br />
  • Solution: <br /> E: 1-T; 2-F; 3-T; 4-F; 5-T <br /> F:- necessity to cope with a new access technology WCDMA <br /> - necessity of backward compatibility towards GSM/GPRS/EDGE <br /> - necessity to design a very efficient battery <br />
  • These 3 visions of a UMTS network are developed in the 3 sections of this chapter. <br />
  • CN <br /> 2 separated domains: Circuit Switched (CS) and Packet Switched (PS) which reuse the infrastructure of GSM and GPRS respectively. <br /> UTRAN <br /> - new radio interface: CDMA <br /> - new transmission technology: ATM <br /> CN independent of AN <br /> The specificity of the access network due to mobile system should be transparent to the core network, which may potentially use any access technique. <br /> Radio specificity of the access network is hidden to the core network. <br /> UE radio mobility is fully controlled by UTRAN. <br /> Some correspondences with GSM: <br /> CNNSSUuUm <br /> UTRANBSSIubA-bis <br /> RNCBSCIurno equivalent <br /> Node-BBTSIu-CSA <br /> UEMSIu-PSGb <br />
  • Principle: to capitalize on existing GSM/GPRS Core Network <br /> MSC (Mobile-services Switching Center) / VLR (Visitor Location Register): switch (MSC) and database (VLR) that serves the user in its current location in CS domain <br /> GMSC (Gateway MSC): switch with a gateway function with the PSTN <br /> SGSN (Serving GPRS Support Node): similar to MSC/VLR in PS domain <br /> GGSN (Gateway GPRS Support Node): similar to GMSC in PS domain <br /> EIR (Equipment Identity Register): database that stores the identities of mobile terminals (can be used for example to set a list of stolen terminals) <br /> HLR (Home Location Register): database of the user’s home system that stores the master copy of the user’s service profile. <br /> Auc (Authentication Center): database for secret keys and algorithms used for authentication and security procedures <br /> VHE (Virtual Home Environment): it is not a physical entity, but a system concept for Personal Service Environment (PSE) portability across network and terminal boundaries. For Release 99, e.g. CAMEL, MExE and SAT are considered the mechanisms supporting the VHE concept. (See subchapter 2.1) <br />
  • An RNS (Radio Network Subsystem) contains one RNC (Radio Network Controller) and at least one Node-B. <br /> The RNC takes a more important place in UTRAN than the BSC in the GSM BSS. Indeed RNC can perform soft HO, while in GSM there is no connection between BSCs and only hard HO can be applied. <br /> A Node-B is also more complex than the GSM BTS, because it handles softer HO. <br /> Controlling RNC (CRNC): a role an RNC can take with respect to a specific set of Node-Bs (ie those Node-Bs belonging to the same RNS). There is only one CRNC for any Node-B. The CRNC has the overall control of the logical resources of its Node-Bs <br />
  • 1°) UE makes a call <br /> 2°) Softer HO <br /> 3°) Soft HO <br /> 4°) Serving RNC (SRNC1): on UL it collects information from the Drift RNC and from its own Node-B and performs selection of the signal on a best frame quality basis. On DL it duplicates Iu-information to Drift RNC and to its own Node-B and recombination of the signal is performed by the UE. There may be only one Serving RNC per UE. <br /> Drift RNC (DRNC2): it performs the routing of information from/to the Serving RNC. There may be up to 4 Drift RNC(s) per UE. <br /> 5°) Temporary state <br /> 6°) SRNS relocation: change of Iu interface. <br /> Former DRNC (DRNC2) becomes SRNC (SRNC2) for that UE, former SRNC (SRNC1) no longer plays a role in the call <br />
  • Hard HO (in the GSM sense) can also be performed, but it is not recommended. <br /> However hard HO must be performed to switch between two different frequencies : it is the case between two different CDMA carriers or between UMTS and GSM. <br /> Note: <br /> The RNC can take different roles in the UTRAN: <br /> - Controlling RNC (CRNC): a role an RNC can take with respect to a specific set of Node-Bs (ie those Node-Bs belonging to the same RNS). There is only one CRNC for any Node-B. The CRNC has the overall control of the logical resources of its Node-Bs. <br /> - Serving RNC (SRNC): a role an RNC can take with respect to a specific connection between UE and UTRAN. There is only one SRNC for each UE that has a connection to UTRAN. The SRNC is in charge of the radio connection between a UE and the UTRAN. SRNC terminates the Iu for this UE. <br /> - Drift RNC (DRNC): a role an RNC can take with respect to a specific connection between UE and UTRAN. A RNC that supports a SRNC with radio resources when the connection between UE and UTRAN needs to use cell(s) controlled by this RNC is referred as DRNC. <br />
  • A manufacturer can produce only the Node-B (and not the RNC). This is not possible in GSM (A-bis is a proprietary interface) <br /> The Iur physical connection can go through the CN using common physical links with Iu-CS and Iu-PS. However there is a direct logical connection between the 2 RNCs: the Iur information is not handled by the CN. <br />
  • In the OSI (Open system Interconnection) reference model: <br /> - NAS refers to higher layers (3 to 7). Entities of this part will exchange tele-services and bearer services. <br /> e.g. CC (Call Control), MM (Mobility Management) and applications <br /> - AS refers to lower layers (1 to 3). Entities of this part will exchange bearer services only. <br /> e.g radio protocols and Iu protocols <br /> Notes: <br /> (1) The radio interface protocols are defined in documents TS 25.2xx and TS 25.3xx from 3GPP. <br /> (2) The Iu interface Protocols are defined in documents TS 25.41x from 3GPP. <br />
  • NAS messages between the CN (CS and PS domains) and the UE are transmitted on a transparent way through the UTRAN using Iu protocols and Radio protocols. <br /> For CS domain: <br /> - CM: Connection Management <br /> - MM: Mobility Management (network mobility management) <br /> - CS traffic <br /> For PS domain: <br /> - SM: Session Management <br /> - GMM: GPRS Mobility Management (network mobility management) <br /> - PS traffic <br />
  • The radio protocols are responsible for exchanges of signalling and user data between the UE and the UTRAN over the Uu interface: <br /> - User plane protocolsThese are the protocols implementing the actual Radio Access Bearer (RAB) service, i.e. carrying user data through the access stratum (EXAMPLES 1,2 and 4). <br /> - Control plane protocolsThese are the protocols for controlling the radio access bearers and the connection between the UE and the network from different aspects including requesting the service (EXAMPLE 5), controlling different transmission resources, handover & streamlining etc... Also a mechanism for transparent transfer of Non Access Stratum (NAS) messages is included (EXAMPLE 3). <br /> Some principles: <br /> The Radio Protocols are independent of the applied transport layer technology (ATM in R99): that may be changed in the future while the Radio Protocols remain intact. <br /> The main part of radio protocols are located in the RNC (and in the UE). The Node-B is mainly a relay between UE and RNC. <br />
  • Note: Transport Network Layer and Radio Network Layer are included in the layers 1 to 3 of ISO/OSI model. <br /> The Iu protocols are responsible for exchanges of signalling and user data between two endpoints of an Iu interface (e.g. Node-B and RNC over the Iub interface): <br /> Radio Network Layer: contains all UTRAN-related issues. <br /> - Application Protocol: the messages of this protocol are used for carrying signalling. The Application Protocol also triggers the establishment and release of Data Bearers (for Data Streams) directly or indirectly (via ALCAP protocol). <br /> - Data Streams: carry user information and can also carry signalling of higher layers. <br /> Transport Network Layer: contains the standard transport technology (ATM will be applied in Release 99). It may be changed without any UTRAN-specific changes. <br /> - ALCAP:- is a generic name for the signalling protocols of the Transport Network <br /> Control Plane used to establish/release Data Bearers. <br /> - makes establishment/release of Data Bearers on request of the <br /> Application Protocol. <br /> - Bearers: - Application Protocol and Data Streams are carried on independent Bearers (Signalling Bearers and Data Bearers respectively) <br /> - ALCAP messages are also conveyed on specific signalling bearers. <br />
  • Note: for the difference between UMTS bearer service, RAB and Radio Bearer, see chapter 2.1 “What is a service?” <br /> A UMTS bearer service is mapped on one or several RAB(s): each RAB can have its own QoS requirements according to the negotiated UMTS Bearer Service. <br /> A RAB must be flexible enough to support different traffic types, activity levels, throughput rates, transfer delays and bit error rates and its QoS parameters may change during an active connection. <br /> A RAB offers a wide range of QoS for both connection oriented packet-switched services, connectionless (store-and-forward) services, and circuit-switched traffic. <br /> However, a RAB no longer makes a distinction between user data coming from CS-domain and PS-domain, which may have adequate QoS, but are handled by the same entities and the same protocol stacks inside the UTRAN. <br /> In the Multi-call case, one AMR RAB from CS domain and one interactive or background RAB from PS domains can be supported simultaneously. <br /> Radio Bearer: The service provided by the RLC layer for transfer of user data between UE and RNC <br />
  • Establishment of a call Inside the CN <br /> CS part: identical procedures as the GSM ones <br /> PS part: identical procedures as the GPRS ones <br /> The CN does not require resource dedicated to the UTRAN but some RAB with a given QoS. <br /> The UTRAN has total freedom to reach the required QoS and set RABs attributes in order to allow efficient use of radio resources. <br />
  • Connection to UTRAN <br /> UE establishes a signaling link with UTRAN: RRC connection establishment <br /> Request for service <br /> UE sends to the RNC its “Connection Management Service Request” through RRC signaling message <br /> RNC forwards the CM service request to the MSC with a RANAP message <br /> Note : If the user originates one or more MO new calls in a multi-call configuration, UE sends a “CM service request” through the existing signaling connection for each new call. <br /> Authentication and ciphering / integrity <br /> Mutual Authentication is performed between Core Network and UE. It is transparent to the UTRAN. <br /> Ciphering is used for confidential data transfer on air interface and Integrity for authentication of signaling messages on air interface (not used in GSM): Ciphering and Integrity keys are calculated during authentication procedure. Both Ciphering and Integrity procedures are implemented in the radio part but activated by the Core Network. <br /> Set-up <br /> UE indicates the bearer capability required for the call. CN translates this bearer capability into a basic service and determines whether an inter-working function is required. <br /> RAB assignment and Radio Bearer Allocation <br /> CN sends an Allocate channel message to UTRAN (“RAB assignment Request”) to trigger UTRAN and UE to set up a traffic channel over the radio interface (Radio Bearer(s) Setup). <br /> Alert and connect <br /> ‘Alert’ to indicate to the calling user that the called party is being alerted. <br /> ‘Connect’ to instruct the calling equipment to connect the speech path. <br /> See 3GPP 23.018 <br />
  • Solution: <br /> B: 1-T; 2-F; 3-T <br /> C: 1-T; 2-T; 3-T <br /> D: 1-T; 2-T; 3-T <br />
  • See http://www.cdg.org for IS-95 <br /> In CDMA field, we have experience of IS-95 <br /> IS-95 vocabulary: <br /> forward channel=downlink <br /> reverse channel=uplink <br /> handoff=handover <br />
  • Spectrum efficiency : transmission capacity per spectrum unit (bandwidth), i.e kbit/MHz. This must not be confused with the traffic capacity. <br /> The spectrum efficiency in UMTS is higher than in GSM (25x200kHz carriers in GSM offering 335 kbps** while a 5 MHz UMTS carrier offers 400 kbps). If we factor in densification (frequency reuse pattern), the UMTS traffic capacity is dramatically increased. According to CDMA Development Group: <br /> “Capacity increases by a factor of between 8 to 10 compared to an AMPS analog system and between 4 to 5 times compared to a GSM system” <br /> ** calculation details: <br /> GSM = 25 x 13,4kbps * 7 TS / 7 (frequency reuse factor) = 335 kbps <br /> UMTS : frequency reuse factor =1!! <br />
  • Code synchronization between the transmitter and the receiver is crucial for de-spreading the wideband signal successfully. <br />
  • What is the spreading factor? <br /> It is the number of chips per bit (=chip rate/bit rate). <br /> The chip rate is linked with the CDMA carrier bandwidth and has a constant value of 3,84 Mcps. <br /> It is quite easy to match the bit rate of the signal with the CDMA chip rate just by choosing the adequate spreading factor. <br /> The higher the spreading factor, the more redundancy you add in the signal and the lower the probability of bit error is by transmitting the signal. <br /> It is also traduced by the processing gain (see below). <br /> Code synchronization? <br /> It is difficult to acquire and to maintain the synchronization of the locally generated code signal and the received signal. <br /> Indeed synchronization has to be kept within a fraction of the chip time. <br /> Note: the operation on the transparency above is N-ExOR <br /> (00 = 1; 01 = 0 ; 10 = 0 ; 11 = 1) <br />
  • What is processing gain? <br /> After de-spreading, the amplitude of the desired signal is higher than that of any interfering signal by a factor called processing gain. <br /> It means that the amplitude of the desired signal could even be below the thermal noise! <br /> That is the reason why its detection is difficult without knowledge of the spreading sequence (spread spectrum systems have found their origin in military applications: the signal is hidden below the omnipresent thermal noise) <br /> W is constant (3,84 Mcps related to CDMA carrier 5MHz): the higher the bit rate, the lower the Processing Gain. <br /> Note that the processing gain and the spreading factor are mathematically identical, although they refer to different concepts. <br /> We can also say that the processing gain is higher with low bit rate, because the spreading factor is higher, i.e you add more redundancy (more chips per bit). <br />
  • The rainbows cells mean that the whole bandwidth (5 MHz) is reused in each cell. <br /> In GSM there is also intra-cell interference when there are 2 (or more) TRXs in the same cell. But it is a small problem (as each TRX runs on a different frequency) <br /> In CDMA intra-cell interference is an important problem. <br />
  • Quasi-orthogonal: it is not necessary to have primary colors at the receiver to separate the user. Red and orange for example can also be distinguished. <br /> Orthogonality between the codes is impossible to maintain after transfer over the radio interface (multi-path on DL, UEs not synchronized on UL ) <br />
  • CDMA is instable by nature: <br /> one user may jam a whole cell by transmitting with too high power <br /> need for accurate and fast power control <br /> too many users in one cell would have the same effect <br /> need for congestion control <br /> A CDMA resource has 2 dimensions: the codes and the power. Obviously the power is the limiting factor ; the better we can control the power usage, the more capacity (users) we can allocate. <br />
  • Spreading consists of two steps: <br /> The channelization code (also called spreading code) transforms every data symbol into a number of chips, thus increasing the bandwidth of the signal. The narrowband signal is spread into a wideband signal with a chip rate of 3.84 Mchips/s. <br /> The system must choose the adequate spreading factor to match the bit rate of the narrowband signal. <br /> The spreading factor is directly linked with the length of the channelization code. <br /> The scrambling code does not affect the signal bandwidth: it is only a chip-by-chip operation. <br /> The scrambling code is cell-specific on the downlink and terminal-specific on the uplink. <br />
  • What is a channelization code? <br /> OVSF (Orthogonal Variable Spreading Factor) <br /> Length: 4-256 chips according to the spreading factor <br /> (in downlink also 512 chips is possible to match very low bit rate) <br /> Number of codes: <br /> The channelization codes can be defined in a code tree, which is shared by several users. <br /> If one code is used by a physical channel, the codes of underlying branches may not be used. <br /> The number of codes is consequently variable: the minimum is 4 codes of length 4, the maximum is 256 codes of length 256. <br /> The channelization code (and consequently the spreading factor) may change on a frame-by-frame basis <br /> How is Code Allocation managed? <br /> The codes within each cell are managed by the RNC. <br /> No need to coordinate code tree resource between different base stations or terminals. <br /> Usually one code tree per cell. If two code trees are used, it is necessary to use the secondary scrambling code. <br />
  • In fact, there are two types of scrambling codes: <br /> Long codes: <br /> Gold codes constructed from a position wise modulo 2 sum of 38400 chip segments of two binary sequences (generated by means of 2 generators polynomials of degree 25) <br /> used with Rake Receiver : the PRACH is constructed from the long scrambling sequences. There are 8192 PRACH preamble scrambling codes in total, divided into 512 groups of 16 each. <br /> Short codes: <br /> Length : 256 chips <br /> used with advanced multi-user detector <br /> likely to be used later <br /> Refer to Technical Specification 3GPP TS 25.213 <br />
  • “A single carrier”: in fact each operator may use several carriers of 5MHz each (2 in Germany, 3 in France) <br /> The rake receiver can only be used with signals on the same carrier. <br />
  • Rake fingers are allocated to the peaks at which significant energy arrives. Update rate: tens of ms <br /> Each finger tracks the fast-changing phase and amplitude values due to fast fading and removes them <br /> Rake Receiver resides in both UE and Node-B. <br /> The numbers of fingers for a Rake Receiver is implementation dependant. <br />
  • * we will see later that it is also possible to multiplex several services on the same code! <br /> Indeed on a dedicated physical channel (which is identified by its spreading code) a user can multiplex several services as long as the total bit rate of the services does not exceed the bit rate of the physical channel. <br /> See subchapter 5.UTRAN/ Physical Layer (Transport Channel Multiplexing) <br />
  • Which codes make possible to separate the two signals at the receiver? <br /> Scrambling codes (the two signals may have the same channelization code) <br />
  • What is multipath propagation? <br /> The signal travels from transmitter to receiver over different paths, due to reflections, diffractions or scattering. Consequently the same signal arrives at the receiver with a little delay. <br /> The chip rate can be considered as the resolution of the CDMA system. It is linked with the 5 MHz carrier. <br />
  • Multi-path propagation usually reduces the quality of the signal. <br /> But in most cases a Rake Receiver can take advantage of multi-path to improve the quality of the signal. Indeed the dispersion is often greater than the chip duration. <br /> Note: with IS-95 (cdmaOne), the carrier bandwidth is about 1 MHz and the chip duration is consequently longer: 1 µs (300 m). Multi-path components can not be separated in urban areas with IS-95. <br />
  • Near-Far problem: <br /> MS1 at the cell edge suffers a path loss, say 70 dB above that of MS2 which is near the base station. <br /> MS1 and MS2 operate within the same frequency, separable at the base station by their respective spreading codes. <br /> If MS2 is not power-controlled, it can easily over-shout MS1 and a large part of the cell. <br /> Cocktail party effect! <br /> We can also refer to the so called cocktail party effect to explain the necessity of power control: if someone speaks too loud, all the people in the room will be disturbed. Without PC a single overpowered mobile could block a whole cell as well. <br /> Power control is crucial on UL (not only a enhancement feature such as in GSM), not on DL, although it is also used for different motivation (no near-far problem due to one-to-many scenario here) <br /> Power classes of the mobile: <br /> Class421 dBm (126 mW) – UMTS phone <br /> Class324 dBm (251 mW) – UMTS phone <br /> Class230 dBm (1W) – GSM/GPRS phone <br /> Class133 dBm (2W) – GSM/GPRS phone <br />
  • Basic mechanism: <br /> PC is intended to reduce the interference level in the system by maintaining the quality if the UE-UTRAN radio link as close as possible to the minimum quality required for the type of service requested. <br /> How is Power Control performed ? <br /> - Open loop power control (also called slow power control): <br /> it consists for the mobile station of making a rough estimate of path loss by means of a DL beacon signal and adding the interference level of the Node-B and a constant value. <br /> It’s far too inaccurate and only used to provide a coarse initial power setting of the mobile station at the beginning of a connection <br /> - Closed-loop power control: <br /> See next slide <br />
  • Inner Loop (Fast Loop Power Control) <br /> In UL, the serving cells should estimate signal-to-interference ratio SIRest of the received uplink DPCH. The serving cells should then generate TPC commands and transmit the commands once per slot according to the following rule: if SIRest > SIRtarget then the TPC command to transmit is "0" , while if SIRest &lt; SIRtarget then the TPC command to transmit is "1". <br /> Upon reception of one or more TPC commands in a slot, the UE shall derive a single TPC command, TPC_cmd, for each slot, combining multiple TPC commands if more than one is received in a slot. TPC_cmd values = +1(power up), -1 (power down), 0 <br /> The step size TPC is under the control of the UTRAN (value = 1 dB or 2 dB) <br /> UE shall adjust the transmit power of the uplink DPCCH with a step of DPCCH (in dB) which is given by DPCCH = TPC  TPC_cmd. <br /> The command rate of 1500Hz is faster than any significant change of path loss. <br /> Outer Loop <br /> The RNC checks the quality of the signal using for example a CRC-based approach (Cyclic Redundancy Check) and uses this result to adjust SIR target for the inner loop. <br /> The big issue is to meet constantly the required quality: no worse and also no better, because it would be a waste of capacity. <br /> The required quality may change with the multi-path profile (related to the environment) and with the UE speed. <br /> The outer loop management is handled by the CRNC because a soft HO may be performed. <br /> Frequency of the outer loop: 10-100 Hz typically <br /> Note: in GSM only slow power control is employed (about 2 Hz) <br />
  • Soft HO: UE is in the overlapping area of two adjacent sectors belonging to two different Node-Bs. <br /> The communication between UE and UTRAN takes place concurrently via two different radio links from each Node-B separately: <br /> - In DL: the Node-Bs make use of two separate scrambling codes. In the UE the two signals are received by means of Rake Processing, which selects the better frame between the two candidates. <br /> - In UL: the UE transmits one signal coded by its scrambling code and this signal will be decoded by the two Node-Bs. In each Node-B the signal are routed to the RNC, which selects the better frame between the two candidates. <br /> Softer HO: UE is in the overlapping area of two adjacent sectors of the same Node-B. <br /> The communication between UE and UTRAN takes place concurrently via two different radio links from each sector separately: <br /> - In DL: the Node-B make use of two separate scrambling codes (one for each sector). In the UE the two signals are received by means of Rake Processing, which selects the better frame between the two candidates. <br /> - In UL: the UE transmits one signal coded by its scrambling code and this signal will be decoded separately by each sector of the Node-B. The 2 signals received are combined using the Maximum Ratio Combining. <br />
  • IS-95: about 30% to 40% of mobile phones are in soft HO <br /> The number of NodeBs to which UE is connected is called “Active Set”. The increase of paths in UL or DL leads to diversity gain. The gain is higher in Soft HO situation than that of the softer HO (because of macro diversity, ie, space between 2 Node Bs is more important than between 2 antennas). <br /> The selection of new link establishment is based on CPICH measurement of the neighbouring cells reported to the SRNC. <br /> HO decision process: <br /> UE receives from the network all the necessary information for measurement reports: Ec/I0, Path Loss, ... <br /> Possible causes that could be used for trigger a HO process (non-exhaustive list): Uplink quality, Uplink signal, measurements; Downlink quality, Downlink signal measurements, Distance, Change of service, Better cell, O&M intervention, Directed retry, Traffic, Pre-emption, … <br /> Other types of HO: <br /> Inter-frequency hard HO (from one CDMA carrier to another) <br /> Inter-mode hard HO (from FDD to TDD) <br /> Inter-system hard HO (e.g between UTRAN FDD and GSM) <br />
  • The Soft Handover procedure is composed of a number of single functions: <br /> Measurements; Filtering of Measurements; Reporting of Measurement results; <br /> The Soft Handover Algorithm; Execution of Handover. <br /> At the start of diversity handover, the reverse link dedicated physical channel <br /> transmitted by the UE, and the forward link dedicated physical channel transmitted <br /> by the diversity handover source Node-B will have their radio frame number and <br /> scrambling code phase counted up continuously as usual, and they will not change at <br /> all. Naturally, the continuity of the user information mounted on them will also be <br /> guaranteed, and will not cause any interruption. <br />
  • UMTS radio dimensioning process is very complex, especially because of the interdependence between coverage, capacity and quality. <br /> No frequency planning required (all users use the same carrier) <br />
  • Why will the cell radius decrease when bit rate increases? <br /> The higher the bit rate, the lower the processing gain, the lower the uplink range. <br /> The cell radius values are only indicative. It belongs to: <br /> thermal noise density, <br /> required Eb/N0, <br /> NodeB noise, <br /> NodeB sensitivity, <br /> NodeB antenna gain, <br /> Rx diversity gain, <br /> service bit rate, <br /> UE speed,... <br /> Those value are estimated for a given BER/BLER, an expected Eb/N0, as well as a reasonable speed. <br /> BER speech in CS : 10-3 <br /> BER data in CS : 10-6 <br /> BLER date in PS : 0,1 <br /> BLER = Block Error Rate <br /> Note: <br /> GSM terminal transmit power is usually 2 W (= 33 dBm). <br />
  • AMR codec: see “Appendix” for more details <br /> What are additional gains from these sources of diversity? <br /> Each type of improvement can provide an additional gain of 1-4 dB according to the environment (a few hundred meters additional uplink range). <br /> But there are no a priori values for any diversity gains, because each gain depends on the degree of the other diversity sources. <br />
  • In the uplink the codes originate from different points: they can not be synchronised. <br /> The number of orthogonal codes is not a hard-blocking limitation. A second scrambling code can be taken if necessary, which gives a second set of orthogonal codes (second code tree). <br />
  • Downlink interference level: <br /> The above DL interference level has to be understood as intra-cell (between the channelization codes). Multi-path propagation and lack of DL synchronization between the DCH lead to a loss of orthogonality on the receiver side. <br /> Note: <br /> The capacity figures above are the results of a calculation taken from “WCDMA for UMTS” (see “Related documentation”). Many assumptions have been made, e.g.: <br /> - all terminals are equally distributed at the edge of the cell <br /> - the amount of inter-cell interference is assumed to be lower in micro cells where streets corners isolate the cells more strictly than in macro cells. <br /> These capacity figures give some typical values, but they are very dependant on the radio environment and may be much changed with other assumptions. <br /> “Breathing cells” means that the coverage of the cell can increase (decrease) when the load of the cell decreases (increases): the cell can breath! <br /> Some ways of capacity improvements: <br /> - soft handover <br /> - better network planning (e.g hot spots) <br /> - more carriers (support of inter-frequency handover) <br /> - transmit diversity <br /> - smart antennas (a smart antenna is an array of antenna elements connected to a digital signal processor. Such a configuration dramatically enhances the capacity of a wireless link through a combination of diversity gain, array gain, and interference suppression. Increased capacity translates to higher data rates for a given number of users or more users for a given data rate per user). <br />
  • Question B: <br /> Coding rate 1/3 means: <br /> for 1 bit of traffic data, 3 bits are sent on the air interface (because a channel coding is added to protect the data on the air interface). Applied before radio modulation. <br /> Solution: <br /> A: 1-F; 2-T; 3-T; 4-F <br /> B1 :SF signal 1= 3,84.106 / [12.103 / (1/3)] = 106,67. SF=64 <br /> SF signal 2= 3,84.106 / [384.103 / (1/2)] = 5 . SF=4 <br /> B2 : PG signal 1= 10 Log10(64) = 18 dB <br /> PG signal 2= 10 Log10(4) = 6 dB <br />
  • Solution: <br /> C: 1-T; 2-F; 3-T <br /> D: 3 <br /> E: 1-F; 2-F; 3-T <br />
  • Solution: <br /> F: 1-T; 2-F; 3-T; 4-T <br /> G: 1-T; 2-F; 3-F; 4-T; 5-T <br />
  • How is the common handling of PS and CS data performed? <br /> There is a unique UTRAN protocol stack and a common set of radio bearers for both the PS and CS domains of the core network. <br /> There is no notion of CS and PS in UTRAN. A radio bearer can convey either CS data or PS data. Indeed a radio bearer can offer a wide range of QoS and thus be adapted to all type of data. QoS will be typically a zero delay constraint for data from CS and low bit error rate for data from PS. <br /> A radio bearer is always applied in connected mode, but the resources are not reserved for the duration of the call. <br /> What is the difference between logical and physical interface? <br /> A logical interface can be conveyed on any physical interfaces (ATM, IP). Iub, Iur and Iu can even be conveyed on the same physical interface! <br /> In the first release (R99) ATM will be used as the main transport mechanism on the logical Iu interfaces, but other technologies such as IP are planned to be used later. <br />
  • A Radio Bearer is the service provided by a protocol entity (i.e. RLC protocol) for transfer of data between UE and UTRAN. <br /> Radio bearers are the highest level of bearer services exchanged between UTRAN and UE. <br /> Radio bearers are mapped successively on logical channels, transport channels and physical channels (Radio Physical Bearer Service on the figure) <br />
  • In the control plane, signalling information (e.g NAS signalling or RRC connection establishment ) is mapped on Signalling Radio Bearers (SRB), which are mapped on Control Logical Channels. <br /> In the user plane, user information (e.g Telephony Speech, Web browsing, SMS Cell Broadcast service) is mapped on User plane Radio Bearers, which are mapped on Traffic Logical Channels. <br /> Logical Channels are mapped on Transport Channels (no distinction between control and user plane at this stage), which are mapped (successively) on: <br /> - Physical Channels on the air interface <br /> - Iub Data Bearers on the Iub interface <br /> - Iur Data Bearers on the Iur interface (in case of soft HO) <br />
  • Please note that RAB (Radio Access Bearer) are only provided in the user plane. <br /> What is a RRC connection? <br /> When the UE needs to exchange any information with the network, it must first establish a signalling link with the UTRAN: it is made through a procedure with the RRC protocol and it is called “RRC connection establishment”. <br /> During this procedure the UE will send an initial access request on CCCH to establish a signalling link which will be carried on a DCCH. <br /> A given UE can have either zero or one RRC connection. <br /> AMR codec:see “Appendix” for more details <br />
  • The logical channels are divided into: <br /> Control channels for the transfer of control plane information <br /> Traffic channels for the transfer of user plane information <br />
  • A transport channel is defined by a Transport Format (TF) which may change every Time Transmission Interval (TTI). <br /> The TF is made of a Transport Block Set. The Transport Block size and the number of Transport Block inside the set are dynamical parameters. <br /> The TTI is a static parameter. <br />
  • What is TTI (Transmission Time Interval)? <br /> - it is equal to the periodicity at which a Transport Block Set is transferred by the physical layer on the radio interface <br /> - it is always a multiple of the minimum interleaving period (e.g. 10ms, the length of one Radio Frame) <br /> - MAC delivers one Transport Block Set to the physical layer every TTI. <br />
  • Solution: <br /> 1. Table <br /> TTI = 40 ms <br /> The TTI is always a multiple of the length of the radio frame (=10 ms). <br /> Transport Block Size = 576 bits <br /> 2. The system will deliver the transport blocks to the physical layer at a bit rate of <br /> 576 bits * 4 /40 ms = 57,6 kbps <br /> This transport channel can be applied to a FAX. <br /> 3. The Transport Format Set (TFS) contains 5 TF(s) (B=0,1,2,3,4) <br /> 4. The transfer may have been reduced so as to give more capacity to a service with a higher priority (e.g real time services) <br />
  • The transport channels are divided into: <br /> Common channels: they are divided between all or a group of UEs in a cell. They require in-band identification of the UEs when addressing particular UEs. <br /> Dedicated channels: it is reserved for a single UE only. In-band identification is not necessary, a given UE is identified by the physical channel (code and frequency in FDD mode) <br />
  • BCH <br /> >high power to reach all the user and low fixed bit rate so that all terminals can decode the data rate whatever its ability: only one Transport Format because there is no need for flexibility (fixed bit rate) <br /> PCH <br /> >only two transport channels can NOT carry user information: BCH and PCH. <br />
  • Note: Beam-forming is also called “Inherent addressing of users”: it is the possibility of transmission to a certain part of the cell. <br /> RACH and FACH are mainly used to carry signalling (e.g at the initial access), but they can also carry small amounts of data. <br /> When a UE sends information on the RACH, it will receive information on FACH. <br />
  • DSCH and CCPH seem to be symmetrical, but: <br /> - DSCH is on the DL, so that different user data are synchronised with each other (the information on whether the UE should receive the DSCH or not is conveyed on the associated DCH) <br /> - CPCH is on the UL, so that different user data can NOT be synchronised (the mobile phones are not synchronised). It may cause big problem of collisions! <br />
  • DCH <br /> > It is different from GSM where TCH carries user data (e.g speech frames) and ACCH carries higher layer signalling (e.g HO commands) <br /> User data and signalling are therefore treated in the same way from the physical layer (although set of parameters may be different between data and signalling) <br /> > wide range of Transport Format Set permits to be very flexible concerning the bit rate, the interleaving... <br /> > Fast Power Control and soft HO are only applied on this transport channel. <br />
  • According to the slide above and the previous one, we can say state that : <br /> Except BCH and PCH, each type of transport channel can be used for the transfer of either control or traffic logical channels. <br />
  • Solution: <br /> (1) logical, (2) transport, (3) physical <br />
  • A. Web-browsing at very low bit rate <br /> B. Web-browsing at very high bit rate <br /> C. UE measurement reporting (UL) <br /> D. Telephony speech <br /> E. SMS Cell Broadcast service (DL) <br /> F. Audio, Video streaming <br /> G. Fax <br /> H. Paging of UE when the network doesn’t know UE location (DL) <br /> I. System Information Broadcasting (DL) <br /> J. Initial access (RRC Connection Establishment) <br />
  • The radio protocols are responsible for exchanges of signalling and user data between the UE and the UTRAN over the Uu interface <br /> The radio protocols are layered into: <br /> - the RRC protocol located in RNC* and UE <br /> - the RLC protocol located in RNC* and UE <br /> - the MAC protocol located in RNC* and UE <br /> - the physical layer (on the air interface) located in Node-B and UE <br /> Two additional service-dependent protocols exists in the user plane in the layer 2: PDCP and BMC. <br /> Each layer provides services to upper layers at Service Access Points (SAP) on a peer-to-peer communication basis. The SAP are marked with circles. A service is defined by a set of service primitives. <br /> Radio Interface Protocol Architecture is described in 3GPP 25.301. <br /> (*except a part of protocol used for BCH which is terminated in Node-B) <br />
  • RRC is a protocol which belongs to control plane. <br /> The RRC functions are: <br /> Call management <br /> RRC connection establishment/release (initial access) <br /> Radio Bearer establishment/release/reconfiguration (in the control plane and in the user plane) <br /> Transport and Physical Channels reconfiguration <br /> Radio mobility management <br /> Handover (soft and hard) <br /> Cell and URA update (see “5.UTRAN/ Mobility Management”) <br /> Paging procedure <br /> Measurements control (UTRAN side) and reporting (UE side) <br /> Outer Loop Power Control <br /> Control of radio channel ciphering and deciphering <br /> RRC can control locally the configuration of the lower layers (RLC, MAC...) through Control SAP. These Control services are not requiring peer-to-peer communication, one or more sub-layers can be bypassed. <br /> See 3GPP 25.331 RRC protocol (over 500 pages!) <br />
  • See 3 GPP 25.323 (PDCP protocol) and 25.324 (BMC protocol) <br />
  • There is no difference between RLC instances in Control and User planes. There is a single RLC connection per Radio Bearer. <br /> RLC main functions: <br /> RLC Connection Establishment/Release in 3 configuration modes: <br /> - transparent data transfer (TM): without adding any protocol information <br /> - unacknowledged data transfer (UM): without guaranteeing delivery to the peer entity (but can detect transmission errors) <br /> - acknowledged data transfer (AM): with guaranteeing delivery to the peer entity. The AM mode provides reliable link (error detection and recovery, in-sequence delivery, duplicate detection, flow Control, ARQ mechanisms) <br /> ARQ=Automatic Repeat Request (it manages retransmissions) <br /> Transmission/Reception buffer <br /> Segmentation and reassembly (to adjust the radio bearer size to the actual set of transport formats) <br /> Mapping between Radio Bearers and Logical Channels (one to one) <br /> Ciphering for non-transparent RLC data (if not performed in MAC), using the UEA1, Kasumi algorithm specified in R’99 <br /> Encryption is performed in accordance with TS 33.102 (radio interface), 25.413, 25.331(RRC signaling messages) and supports the settings of integrity with CN (CS-domain/PS-domain) <br /> 3GPP 25.322 RLC protocol <br />
  • MAC belongs to control plane and to user plane. <br /> MAC main functions: <br /> Data transfer: MAC provides unacknowledged data transfer without segmentation <br /> Multiplexing of logical channels (possible only if they require the same QoS) <br /> Mapping between Logical Channels and Transport Channels <br /> Selection of appropriate Transport Format for each Transport Channel depending on instantaneous source rate. <br /> Priority handling/Scheduling according to priorities given by upper layers: <br /> - between data flows of one UE <br /> - between different UEs <br /> Priority handling/Scheduling is done through Transport Format Combination (TFC) selection <br /> Reporting of monitoring to RRC <br /> Ciphering for RLC transparent data (if not performed in RLC) <br /> 3GPP 25.321 MAC protocol <br />
  • Note: CCTrCH = Coded Composite Transport Channel <br /> MAC can re-select another TFC (inside TFCS) every TTI. <br /> TFC selection is based on: <br /> - RLC buffer status <br /> - RB attributes (e.g traffic class) <br /> - Power indication from layer 1 <br /> By selecting TFC, MAC can: <br /> - handle priorities between UEs (with common transport channels) <br /> - handle priorities between data flows of one UE <br /> - scheduling the transport blocks <br /> TFS and TFCS are assigned to MAC by RRC. <br />
  • The physical layer belongs to control plane and to user plane. <br /> Physical layer main functions: <br /> Multiplexing/de-multiplexing of transport channels on CCTrCH (Coded Composite Transport Channel) even if the transport channels require different QoS. <br /> Mapping of CCTrCH on physical channels <br /> Spreading/de-spreading and modulation/demodulation of physical channels <br /> RF processing (3 GPP 25.10x) <br /> Frequency and time (chip, bit, slot, frame) synchronization <br /> Measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power, etc.) <br /> Open loop and Inner loop power control <br /> Macro-diversity distribution/combining and soft handover execution <br /> 3GPP 25.2xx <br />
  • ... <br />
  • Solution: <br /> 1. See Subchapter 5.1 <br /> a UE which makes web browsing while downloading e-mails will use 2 DTCHs. A UE which makes a call uses 3 coordinated DTCHs. <br /> 2. MAC-b for broadcast transport channel (BCH) <br /> MAC-c/sh for control/shared transport channels <br /> MAC-d for dedicated channels <br /> 3. One MAC-d per UE (UTRAN side) and one MAC-d per UE (UE side), located in SRNC and in UE. <br /> Note: One MAC-b per cell (UTRAN side) and per UE (UE side), located in Node-B and in UE. <br /> One MAC-c/sh per cell (UTRAN side) and per UE (UE side), located in CRNC and in UE. <br /> 4. Dedicated Traffic logical channels can be mapped on common transport channels (Channel Switching) <br /> 5. See Subchapter 5.2 <br /> 6. true (because MAC multiplexing is performed before channel coding) <br />
  • 7. RNTI is used for inband identification of UEs for common transport channels. For dedicated transport channels one UE is identified by the physical channel. <br /> 8. In the physical layer (see further in this chapter for more details) <br /> 9. CCTrCH (Coded Composite Transport Channel) <br /> 10. TFC selection is performed by MAC and TFC is assigned by RRC <br /> 11. yes/yes/no (TFC selection is made either in MAC-c/sh or in MAC-d: it is impossible to multiplex a common and a dedicated transport channel) <br /> 12. no (no interaction with RRC when selecting TFC inside TFCS) <br /> 13. MAC measurement reports enables RRC to detect a need for transport channel reconfiguration, e.g switch from a common to a dedicated transport channel. <br />
  • The Iu protocols are responsible for exchanges of signalling and user data between two endpoints of an Iu interface (e.g. Node-B and RNC over the Iub interface) <br />
  • Note: AAL2 and AAL5 are sub-layers of ATM which provide some adaptation between the application (voice, data, signalling) and the ATM layer. <br /> NBAP <br /> is used to carry signalling (e.g Radio Link Establishment) <br /> Examples of actions of NBAP during Radio Link Establishment: <br /> - signalling exchanges over Iub, which permits the RNC to reserve radio resources of Node-B for the Radio Link <br /> - signalling transaction with ALCAP, which will setup a Iub data bearer (on AAL2) to carry the Radio Link <br /> Frame Protocols <br /> At this stage Data Streams (carrying RABs, NAS signalling, SMS Cell Broadcast service, RRC connection establishment…) have been mapped on transport channels <br /> The Frame Protocols (FP) define the structures of the frame and the basic in-band control procedures for every type of transport channels. <br /> ALCAP <br /> is used to set up AAL2 connections for Data Streams. <br /> Bearers <br /> Data Streams are carried on AAL2, which enables better bandwidth efficiency for user packets but requires its own signalling (ALCAP signalling is used to set up AAL2 connections for Data Streams). <br /> NBAP and ALCAP messages are carried on AAL5. <br />
  • Note: AAL2 and AAL5 are sub-layers of ATM which provide some adaptation between the application (voice, data, signalling) and the ATM layer. <br /> RNSAP <br /> It is used to carry signalling (e.g Radio Link Establishment) <br /> e.g. actions of RNSAP during Radio Link Establishment: <br /> - signalling exchanges over Iur: the SRNC request the DRNC to reserve radio resources for the Radio Link (the DRNC will afterwards reserve these radio resources in the suitable Node-B) <br /> - signalling transaction with ALCAP, which will setup a Iur data bearer to carry the Radio Link <br /> Frame Protocols <br /> At this stage Data Streams (carrying RABs, NAS signalling, SMS Cell Broadcast service, RRC connection establishment…) have been mapped on transport channels <br /> The Frame Protocols (FP) define the structures of the frame and the basic in-band control procedures for every type of transport channels. <br /> ALCAP <br /> It is used to set up AAL2 connections for Data Streams. <br /> Bearers <br /> Data Streams are carried on AAL2, which enables better bandwidth efficiency for user packets but requires its own signalling (ALCAP signalling is used to set up AAL2 connections for Data Streams). <br /> RNSAP and ALCAP messages are carried on AAL5. <br />
  • 1. What is the path of CS traffic through these protocol stacks? <br /> 2. Same question for PS traffic? <br /> 3. Same question for NAS signalling? <br /> 4. Same question for RRC signalling? <br /> 5. Which protocol is responsible for establishing AAL2 bearers? what is the path of this protocol? <br /> 6. Which protocol is responsible for the signaling exchange between RNC and Node-B? What is the path of this protocol? <br /> 7. Which protocol is responsible for the signaling exchange between SRNC and DRNC? <br />
  • NAS: Non Access Stratum <br />
  • “Just after switch on” process contains: <br /> Cell selection (including cell search procedure) <br /> PLMN selection <br /> Attachment procedure (see “Appendix” for more details) <br /> See “5.5 Signaling procedures” for BCCH <br /> See “5.6 Physical Layer” for Cell search Procedure <br /> The UE must enter the connected mode to transmit signalling or traffic data to the network <br /> What is the relationship with the states of the mobile phone in GSM? <br /> The two GSM states, idle mode and connected mode, are similar to idle mode and cell_DCH state in UMTS. <br /> What is the relationship with the states of the mobile phone in GPRS? <br /> There is no correspondence between GPRS states (idle, standby and ready) and UMTS states. Indeed there is no notion of connection on GPRS. <br /> . <br />
  • There is either zero or one RRC connection between one UE and UTRAN. If there are more than one signalling connections between the UE and the network, they all share the same RRC connection. <br /> A RRC connection can have up to 4 SRBs (Signalling Radio Bearer), ie up to 4 DCCHs. The DCCH(s) is (are) setup during RRC connection establishment, but can be reconfigured during the time of RRC connection. <br /> The DCCH(s) is (are) used to carry any type of signalling dedicated to this UE, <br /> e.g radio bearer set-up (used to establish a Dedicated Traffic Channel DTCH ), radio measurement reports, location update… <br /> See “5.5 Signaling procedures” RRC Connection establishment. <br />
  • The initial state of the UE is determined by the DCCH established during RRC connection establishment: <br /> - if the DCCH is mapped on a DCH, the UE is in cell_DCH state <br /> - if the DCCH is mapped on RACH/FACH, the UE is in cell_FACH state <br /> The UE can move from one state to another during the time of the RRC connection. Transitions between states are: <br /> - based on traffic volume measurements and network load <br /> - always triggered by UTRAN signalling <br /> Note: in cell_DCH state, the DSCH transport channel can also be used. <br />
  • URA: UTRAN Registration Area (a small set of cells) <br /> Cell_PCH and URA_PCH states are needed for non real time services to optimise usage of codes and battery consumption. It would not be efficient to allocate permanently a DCH which would be used a very low percentage of time (Web application for example) <br /> What is the difference between idle mode, Cell_PCH and URA_PCH states? <br /> In idle mode the location of the UE is not known by the UTRAN, but only by the CN at a Location Area (LA) or Routing Area (RA) level (LA and RA and sets of cells larger than URA, see Subchapter “5.8 Mobility Management” for more details) <br /> The paging message PCH must hence be sent in a LA or in a RA when the UE is in idle mode, whereas it only needs to be sent in a cell in Cell_PCH state or in an URA when the UE is in URA_PCH state (hence the paging procedure is much faster). <br />
  • UE StatesCNUTRAN <br /> UE IdentifiersUE LocationUE IdentifierUE Location <br /> idle modeIMSI, TMSILA, RAno identifierunknown <br /> connected mode <br /> cell_DCHIMSI, TMSILA, RA*RNTIcell <br /> cell_FACHIMSI, TMSILA, RA*RNTIcell <br /> cell_PCHIMSI, TMSILA, RA*RNTIcell <br /> URA_PCHIMSI, TMSILA, RA*RNTIURA <br /> * Furthermore the CN knows the SRNC of the UE <br />
  • Does the UE need to read all the SIBs each time a broadcast is repeated? <br /> Dynamic (i.e frequently changing) parameters are grouped into different SIBs from the more static parameters. The UE reads regularly the SIBs containing dynamic parameters, whereas it reads the SIBs containing static parameters only if the “value tag” of the master information block has changed. <br /> The UTRAN can also inform of the change in system information with Paging messages send on PCH or System Information Change Indication sent on FACH. <br /> CN originated broadcast information : Location Area, Routing Area, mobile network code, mobile country code,... <br /> RNC originated broadcast information : URA, serving and neighbouring cell scrambling codes, RACH info,... <br /> Node B originated broadcast information : interference level,... <br />
  • . <br />
  • LA = Location Area <br /> RA = Routing Area <br /> URA = UTRAN Registration Area (group of cells smaller than LA or RA) <br /> (see subchapter “5.8 Mobility Management”) <br /> Note: <br /> PCH can also be used: <br /> - to change the UE state from cell_PCH or URA_PCH to cell_FACH <br /> - to indicate change in the system information <br />
  • UE is in idle mode: <br /> 1. CN initiates the paging of a UE over a LA (RA in PS domain) spanning, for example, two RNCs. <br /> 2. Paging of UE with Paging Type 1 <br /> LA: Location Area, RA: Routing Area (see subchapter “5.8 Mobility Management”) <br /> A similar procedure applies to UE in cell_PCH or in URA_PCH states. <br />
  • UE is in cell_FACH or in cell_DCH states: <br /> 1. CN initiates the paging of a UE to Serving RNC <br /> 2. Paging of UE with Paging Type 2 (on DCCH) using the existing RRC connection <br />
  • Note: <br /> There is either zero or one RRC connection between one UE and UTRAN. <br /> If more than one signalling connections between UE and CN exist, they all share the same RRC connection. <br /> A RRC connection can have up to 4 SRBs (Signalling Radio Bearer). <br />
  • 1. UE initiates set-up of an RRC connection <br /> Initial UE identity: e.g TMSI <br /> Establishment cause: e.g traffic class <br /> 2. RNC decides which transport channel to setup (RACH/FACH or DCH) and allocates RNTI (Radio Network Temporary Identity) and radio resources (e.g TFS, TFCS, scrambling codes) for this RRC connection. <br /> 3. A new radio link must be setup. This is done via a signalling procedure between RNC and Node-B which is managed by NBAP protocol (see “Procedure D” for more detail). <br /> 4. Logical, transport and physical channel configuration are sent to the UE. <br /> 5. RRC Connection Setup Complete message is sent: <br /> - on RACH in case of RRC connection on RACH/FACH (cell_FACH state) <br /> - on DCH in case of RRC connection on DCH (cell_DCH state) <br />
  • In this example, the UE is in macro-diversity on two Node-Bs from two different RNCs. Therefore the UE could only be in cell_DCH state (soft HO is only possible on DCH) <br /> 1. The CN initiates the release of RRC connection <br /> 2. - <br /> 3. SRNC initiates release of Iu Bearer using ALCAP protocol <br /> 4. - <br /> 5. - <br /> 6. SRNC initiates release of radio link (for Node-B of SRNC) using NBAP protocol <br /> 7. SRNC requires release of radio link (for Node-B of DRNC) to DRNC using RNSAP protocol <br /> 8. DRNC initiates release of radio link (for Node-B of DRNC) using NBAP protocol <br />
  • This procedure is used in many RRC procedures, e.g RRC connection establishment (Procedure C1), Radio Bearer Set-up (Procedure F1), soft HO (Procedure G)… <br /> In this procedure: <br /> - a radio link is set up by the RNC on the Node-B side using the NBAP protocol (a similar task is performed on the UE side using RRC protocol, see e.g. procedure C1) <br /> - a terrestrial link (AAL2 bearer) is setup on Iub interface using ALCAP protocol <br />
  • UE must be in cell_FACH or in cell_DCH states. <br />
  • RAB: Radio Access Bearer <br /> RB: Radio Bearer <br /> Note: <br /> The Signalling Radio Bearers (SRB) are normally set-up during the RRC Connection Establishment procedure but can also be controlled with the normal Radio Bearer procedures. <br />
  • Can the UE send user information (e.g voice call) just after Radio Access Bearer establishment? <br /> YES : At the end of this signaling procedure, a RAB has been assigned to the UE to carry user information. The RAB is mapped on the RB which has been set up. The RB is mapped on DTCH: RACH/FACH or DCH. <br />
  • In this example, the UE is in macro-diversity on two Node-Bs from two different RNCs. Therefore the UE could only be in cell_DCH state (soft HO is only possible on DCH) <br /> This example corresponds to the downlink scrambling code reconfiguration on the Node-B of the DRNC. This new scrambling code can be used, for example, with beam forming antennas. <br /> On the diagram : <br /> 3. Physical Channel Reconfiguration Request <br /> 4. Physical Channel Reconfiguration Command <br />
  • UE could only be in cell_DCH state (soft HO is only possible on DCH). <br /> This example corresponds to a soft HO between two Node-Bs of two different RNCs. <br /> The Active Set is the set of cells to which the UE is connected. <br />
  • Note: “Just after switch on process” is described in more details in subchapter 5.4“UE identifiers”… <br /> Location update is a procedure used for Mobility Management purposes (more details in subchapter 5.8 “Mobility management” : the UE has entered a new Location Area (LA) and uses this procedure to send the new LA to the CN. <br />
  • Note: “Just after switch on process” is described in more details in subchapter 5.4”UE identifiers”… <br /> Mobile terminated call occurs typically when a fixed telephone calls a mobile phone (UE). <br />
  • Note: rate matching, 1st interleaving and 2nd interleaving have not been represented to simplify the figure. <br /> Channel Coding aims at providing protection against transmission errors by inserting some redundancy. <br />
  • After channel coding each transport block is split into radio frames of 10 ms. <br /> The bit rate may be changed for each frame. <br /> Each radio frame is also split into 15 time slots. <br /> But all time slots belong to the same user (this slot structure has nothing to do with the TDMA structure in GSM). <br /> All time slots of a same TDMA frame have the same bit rate. <br /> Fast power control may be performed for each time slot (1500 Hz). <br /> The number of chips for one bit M is equivalent to the spreading factor. It can easily be computed with knowledge of N: <br /> In fact the spreading factor must be equal to 4, 8, 16…256. <br /> Consequently it may be necessary to add some padding bits to match the adequate value of spreading factor (rate matching). <br />
  • CCTrCH: Coded Composite Transport Channel <br /> Example: <br /> DCH 1 carries voice and DCH 2 carries E-mail (for the same user). <br /> Transport Channel Multiplexing is performed after Channel Coding and enables these two services to be mapped onto the same physical channel. <br /> It allows share of a spreading code and consequently share of power. <br /> There are some restrictions with transport channel multiplexing (See 3GPP 25.212) : <br /> - only dedicated transport channels for the same user can be multiplexed on one CCTrCH. <br /> - one dedicated and one common channel can not be multiplex into the same CCTrCH. <br /> - for common channel, only FACH and PCH may belong to the same CCTrCH. <br /> - One CCTrCH can be mapped onto one or several physical channels. <br /> - Different CCtrCH cannot be mapped on the same physical channel. <br /> - In uplink, a maximum of one CCTrCH is allowed for one UE. <br />
  • Physical channels are conveyed only up to Node-B. <br />
  • A layer 1 connection consists of a single DPCCH and zero, one or several DPDCHs. <br /> Several DPDCHs can be used to provide high bit rate. <br /> The different fields of a DPCCH mean: <br /> - known Pilot bits to support channel estimation for coherent detection <br /> - TFCI (Transport Format Combination Indicator): it indicates the format combination of the transport channels mapped onto the physical channels. <br /> - FBI (Feedback Information): will be used later for TX diversity <br /> - TPC (Transmit Power Control): it is the command (“power up” or “power down”) in the closed loop power control. <br /> There is one and only one uplink DPCCH on each radio link, always under a SF of 256; i.e there are 10 bits per uplink DPCCH slot. <br /> UL DPDCH format <br />
  • The Random Access Transmission of the PRACH is split into 2 parts: <br /> -Preamble part: 256 repetitions of a 16 chips signature under scrambling code (constructed from the long scrambling code sequences). Detected by the base station and acknowledged, before the mobile can send the <br /> -Message part (see below): contains the data, similar structure as DPDCH <br /> There is 8192 preamble scrambling codes divided into 512 groups of 16 codes each with a 1:1 correspondence with the primary scrambling code (i.e 16 scramble RACH codes per cell). <br /> The preamble detector is capable of processing simultaneously 16 signatures with a cell radius of 7 km <br />
  • Physical channels are conveyed only up to Node-B. <br />
  • Why are DPDCH and DPCCH time-multiplexed (and not transmitted simultaneously as in UL)? <br /> Discontinuous transmission can cause audible interference to audio equipment close to the terminal (e.g hearing aids), which is a disturbance for user. <br /> In UL the transmission is always continuous, because there is at least the DPCCH which is transmitted. The user will not be disturbed. <br /> In DL the transmission may be discontinuous, but it is no problem (no user at the base station). <br /> Note: The downlink DPDCH/DPCCH physical channels are called the DPCH physical channel. <br /> A few DL DPCH formats <br />
  • The P-CCPCH is time multiplexed with the SCH which is transmitted during the first 256 chips. <br /> P-CCPCH timing is identical to that of SCH and CPICH (see 3GPP 25.211). <br /> The P-CCPCH contains no layer 1 information. <br /> Even if the PCCPCH is not transmitted during the 256 first chips of each slot (SCH), the scrambling code is aligned with the PCCPCH frame boundary, i.e the first complex chip of the PCCPCH frame is multiplied with chip number zero of the scrambling code. <br /> The Secondary CCPCH, which is used to carry FACH and PCH information, is scrambled under the Primary scrambling code as well. <br />
  • The CPICH, or Primary CPICH (because it is used for the cell search procedure), provide the phase and power reference for all other physical channels. <br /> It carries 2 pre-defined symbol sequences used for DL antenna diversity (sequence 1 for antenna 1 and sequence 2 for antenna 2, both under the same channelization and the primary scrambling code. <br />
  • The SCH is time-multiplexed with the P-CCPCH and consists of two sub channels: <br /> - the Primary SCH: common to all UTRAN cells of all operators <br /> - the Secondary SCH: contains a sequence of 15 codes which identifies the Code Group of the cell scrambling code (the 512 downlink scrambling codes are sorted in 64 Code Groups of 8 codes) <br /> Cell Search Procedure (also called synchronisation procedure) <br /> 3GPP does not specified this procedure, but provides an informative description how it is typically done( see 3GPP 25.214 for more details): <br /> Step 1: slot synchronization <br /> The UE uses the Primary SCH to acquire slot synchronization to a cell. <br /> Step 2: frame synchronization and code-group identification <br /> The UE uses the Secondary SCH to find the frame synchronization and identify the Code Group of the found cell (64 possibilities). <br /> Step 3: (downlink) scrambling code identification <br /> The UE determines the (primary) scrambling code used by the found cell through symbol-by-symbol correlation over the CPICH (pilot) with all codes within the Code Group identified in the step 2 (8 possibilities). <br /> Afterwards the P-CCPCH can be detected and the system- and cell specific BCH information can be read. <br /> Note: If the UE has received information about which scrambling codes to search for, steps 2 and 3 above can be simplified. <br />
  • No surprise: each transport channel has its own physical channel, except FACH and PCH which share the same physical channel (S-CCPCH) <br />
  • Bit rate of RB =4*640 bits / 40 ms = 64 kbps <br /> (it is assumed that there is no RLC and MAC overhead for this service) <br />
  • Solution: <br /> Radio Frame Length = 10 ms <br /> Bit Rate (after channel coding) ~ 1971/ 10 ms = 197,1 kbps <br /> SF ~ 3,84 Mcps/ 197,1 kbps ~ 19,5 <br /> We deduce SF=16 <br /> (We can now compute the exact value of the bit rate: <br /> Bit Rate (after channel coding) = 3,84 Mcps/16 = 240 kbps, ie 2400 bits per radio frame <br /> We need 2400-1971 = 429 bits of Rate matching if this service is sent without multiplexing) <br />
  • Solution: <br /> Bit rate of SRB = (148 bits - 12 bits) / 40 ms = 3,4 kbps <br />
  • Solution: <br /> Radio Frame Length = 10 ms <br /> Bit Rate (after channel coding) ~ 129/ 10 ms = 12,9 kbps <br /> SF ~ 3,84 Mcps/ 12,9 kbps ~ 297 <br /> We deduce SF=256 <br /> (We can now compute the exact value of the bit rate: <br /> Bit Rate (after channel coding) = 3,84 Mcps/256 = 15 kbps, ie 150 bits per radio frame <br /> We need 150 - 129 = 21 bits of Rate matching if this service is sent without multiplexing) <br />
  • 2nd interleaving: <br /> This interlacing process (very similar to the 1st interleaving) is applied on the radio frames. Radio frame bits are originated from 1 or several transport blocks. The interlacing is taking place before the segmentation in Time Slot. The matrix has a fixed number of colons set to 30. <br /> This example can be applied to multiplex ISDN service (carried on DTCH/DCH) and signalling (carried on DCCH/DCH). <br />
  • UE dedicated functions: <br /> Aim at maintaining the required quality of service for a minimum amount of radio resources <br /> UTRAN dedicated functions: <br /> Aim at managing the usage and sharing of radio resources among all users connected to the different cells <br /> Additional info for CRNC specificity: Dynamic scheduling on S-CCPCH/DSCH whether CRNC is the serving or a drift RNC <br /> Packet scheduler: <br /> - located in RNC <br /> - allocates bit rate for a bearer and may change this bit rate if required during a connection (bandwidth on demand) <br /> - gets information from measurements reports from the Node-Bs <br /> - part of network load control, because it can reduce the bit rates of packet bearers, if the load become too high (especially load of non controllable real-time users). <br /> Node B handles specific functions as RACH handling, inner loop power control for the closed loop and computes the dedicated measurements <br />
  • RRM Strategy: <br /> RRM function aims at maximizing the traffic load that can be supported in each cell, while avoiding congestion or radio overhead. However the maximum acceptable traffic load per cell heavily belongs to : <br /> Propagation conditions <br /> MS’s speed <br /> MS’s distribution <br /> Traffic distribution <br /> Maximum transmit capacity <br /> RACH and FACH have no feedback channel: they cannot used fast closed loop power control (fast PC). <br /> Characteristics of packet traffic: <br /> - bursty <br /> - tolerates longer delay than real-time services <br /> - can be retransmitted by the radio link control (RLC) to have better bit error ratio (BER) <br />
  • What actions can be taken in case of congestion? <br /> - “power up” deny in fast loop power control <br /> - handover to another CDMA carrier <br /> - handover to GSM <br /> - decrease AMR speech codec bit rates (see “Appendix” for more details) <br /> reduce the throughput of packet data traffic by physical channel reconfiguration (DCH/DCH to DSCH/CPCH or FACH/RACH) <br />
  • The mechanisms of the idle mode (cell reselection, LA/RA update) run also when UE is in connected mode. <br />
  • LA: Location Area, RA: Routing Area <br /> URA: UTRAN Registration Area (it is a set of cells smaller than LA or RA) <br /> See “5.8 Signaling procedures” for RRC Connection establishment. <br /> See “5.5 UE identifiers and UE states” for Just after switch process <br />
  • Radio criteria refers to: <br /> - cell available/unavailable, <br /> - cell barred/not barred <br /> - received level <br /> - quality <br /> - hysteresis (to avoid too many reselections especially when the mobile is located at the border of two cells) <br /> The UE will use the pilot channels (CPICH) of each candidate cell to perform ranking. <br /> Of course, each CPICH is under the scrambling code of the correspondent cell, but the UE can get knowledge of these codes by monitoring the BCH of its current cell. <br />
  • LA and RA are managed on an independent way, but a RA must always be included in one LA (and not be divided into several different LAs). <br /> LA update is performed by the NAS layer MM (Mobility Management) located in UE and in MSC. RA update is performed by NAS layer GMM (GPRS Mobility Management) located in UE and in SGSN. <br /> In the Core Network, the location information is stored on databases: <br /> - HLR (Home Location Register) <br /> It stores the master copy of user’s service profile, which consists of information on allowed services, forbidden roaming areas,… and which is created when a new user subscribes to the system. <br /> The HLR also stores the serving system (MSC/VLR and/or SGSN) where the terminal is located. <br /> - VLR (Visitor Location Register) <br /> It serves the terminal in its current location for CS services and holds a copy of the visiting user’s service profile. <br /> It stores the Location Area (LA) where the terminal is located. <br /> - SGSN (Serving GPRS Support Node) <br /> It serves the terminal in its current location for PS services and holds a copy of the visiting user’s service profile. <br /> It stores Routing Area (RA) where the terminal is located. <br />
  • Cell size &lt; URA size &lt; RA size &lt; LA size <br /> Cell_PCH or URA_PCH? <br /> For a fast moving UE, the URA_PCH state is better than the cell_PCH state, because the URA update frequency will not as high as cell update frequency would be. <br /> Cell update (URA update) is performed after cell reselection (if the new cell does not contain the URA for URA_PCH)or after expiry of periodic cell update (URA update)timer. <br /> The UE must move to the cell_FACH state, execute the cell update (URA update) procedure and reenter the cell_PCH state (URA_PCH state). <br />
  • What is the difference between soft HO and hard HO? <br /> In soft HO the mobile keeps in the same carrier and can manage two radio links simultaneously. The former radio link may be released a long time after the establishment of the radio link with the target base station. <br /> In hard HO the mobile changes the carrier and consequently can not manage two radio links in parallel. The former radio link has to be released before the establishment of the radio link with the target base station. <br /> Please note that there is a third type of handover called seamless handover, where the former radio link is released during the establishment of the radio link with the target base station. This is applied in systems like DECT, but not in UMTS. <br />
  • Methods for compressed mode: <br /> DL : puncturing / reduction of SF by 2 / higher layer scheduling <br /> UL : reduction of SF by 2 / higher layer scheduling <br /> This usually leads the MS to transmit with a higher power. In order to make sure that the gap occurs at the same time in UL and DL, it is advised to use the same method in both directions. The method is chosen by the SRNC according to the bearer type (real time or non real time), the code tree utilisation (for SF/2), then the RNC indicates the purpose of each compressed mode : TDD measurements, GSM BSIC initial identification, ... <br /> SF/2 : the same scrambling can be used or an alternative one (with the risk of creating additional intra-cell interference by loss of orthogonality). <br /> Problem: how can the quality be kept when performing a handover from UMTS to GSM? <br /> see 3GPP 22.129 <br />
  • Solution: <br /> 1. For the initial cell selection, the UE has no information about the (downlink)scrambling code of the cell: it may be any of the 512 codes used in UTRAN and the UE must perform the entire cell search procedure to find it. For the cell reselection, the UE knows from the broadcast channel (BCH) the scrambling codes of the neighbouring cells. The cell search procedure is hence simplified. <br /> 2. Cell reselection consists of selecting a new cell according to radio criteria. Cell update is a signalling procedure used by the UE to inform the UTRAN that a new cell has been selected. Cell update is performed after cell reselection. <br /> 3. In case of a mobile terminated call, the network would have to search the UE in the whole network without LA/RA mechanisms, because it would have no information about the location of the UE. <br /> 4. A small LA would reduce the amount of signalling messages for paging in case of mobile terminated call, but would increase the amount of signalling messages for updating LA (especially if the UE is moving fast). A large LA would produce the opposite effect. Hence a trade off must be found concerning the size of the LA <br /> 5. no soft HO for RACH and FACH transport channels <br /> 6. URA_PCH is better than cell_PCH for a fast moving UE. <br />
  • PLMN selection (if HPLMN not available) <br /> The priority rules takes into account agreement between operators or radio criteria. A manual selection may also be allowed. <br /> The UE must check periodically if the HPLMN is still not available. If the HPLMN becomes available, the UE shall move to it. <br />
  • The IMSI attach is performed immediately after switch on, while the GPRS attach may be performed immediately after switch on or later as the user decides to use services of PS domain. <br /> The IMSI attach and the GPRS attach procedures may be combined by using the optional Gs interface between the MSC/VLR and the SGSN. <br /> After the attachment procedure, the UE is in idle mode and able to be paged. The cell selection process is going on and there may be some changes, especially if the UE is moving: <br /> - a new cell may be selected (e.g. if there are better radio criteria) <br /> - a new PLMN may be selected (e.g. if the current PLMN is no more available) <br /> - LA update is performed (and also RA update, if the UE is GPRS attached) <br />
  • The AMR_12_20 will provide the best quality in case of low load network or good radio propagation conditions. The other modes are better suited in case of high loading or bad radio conditions, but provides a slightly lower speech quality. <br /> For each AMR mode, the AMR codec operates on speech frames of 20 ms and delivers 3 classes of bits sorted on their sensitivity to errors : class A (the most sensitive), class B, class C. <br /> A stronger channel coding will be further applied for class A than for class B and C <br /> Each class requires a transport channel (need for 3 DCH for speech) <br /> The AMR codec can have asymmetric AMR mode adaptation (different modes on UL and DL) <br /> In GSM, the codec is controlled by the BTS; this solution is not applicable in UMTS due to soft handover procedure. Thus the AMR mode control function should be part of the RNC (it belongs to RRM). <br /> See 3GPP 26.071 <br />

Utran description-3-days (1) Utran description-3-days (1) Presentation Transcript

  • UMTS/ UTRAN Introduction © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 1
  • Introduction to UMTS Table of contents 1. Introduction 2. Services Provided 3. UMTS system description 4. WCDMA for UMTS 5. UTRAN (Release 1999) Appendix Related Documentation Abbreviations and acronyms © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 2
  • 1. Introduction © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 3
  • 1.Introduction Definition Universal Mobile Telecommunication System “UM TS is o ne o f the m a jo r ne w third g e ne ra tio n m o bile c o m m unic a tio ns s y s te m s be ing d e ve lo p e d within the fra m e wo rk whic h ha s be e n d e fine d by the I a nd kno wn a s TU I T-2 0 0 0 ” M UMTS Forum © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 4
  • 1. Introduction 1.1 Context 1.2 Standardization 1.3 UMTS goals 1.4 UMTS technical overview © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 5
  • 1.Introduction/1.1 Context Past mobile systems (1) First Generation (1G) In the early 80’s, analog systems e.g Radiocom 2000, C-Netz… Service: speech Limitations of 1G: •poor spectrum efficiency •expensive and heavy user equipment •mobility only in a small area •no security of communications © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 6
  • 1.Introduction/1.1 Context Past mobile systems (2) Second Generation (2G) In the early 90’s, digital systems Europe : GSM US : IS-95 (also called cdmaOne), IS-136 (TDMA system) Japan : PDC Services: Speech and low data rate Limitations of 2G: • Congestion more than 300 million wireless subscribers worldwide -->need to increase system capacity • Limited mobility around the world -->need for a global standardisation • Limited offer of services more than 200 million internet users--> Need for new multimedia services and applications (video telephony, e-commerce...) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 7
  • 1.Introduction/1.1 Context Technical solutions Two types of solutions were possible : • enhancement of 2G system --> 2,5G low cost but short term e.g.: HSCSD, GPRS, EDGE for GSM evolution • design of a complete new standard --> 3G high cost, long term, but great amount of new potential services e.g: UMTS © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 8
  • 1.Introduction/1.1 Context GSM evolution (1) HSCSD (High Speed Circuit Switched Data) Principle: to enhance channel coding scheme and to bundle GSM time slots on a circuit-switched basis. Performance: up to 115,2 kbps Already implemented but not all operators/manufacturers have made this choice. GPRS (General Packet Radio Service) Principle: to enhance channel coding scheme and to bundle GSM time slots on a packet-switched basis (the allocation of time slots is performed dynamically at the initialisation and during the connection) Performance: up to 171,2 kbps 1999/2000 : deployment phase 2002 : service offers for most operators © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 9
  • 1.Introduction/1.1 Context GSM evolution (2) EDGE (Enhancement Data rates for GSM evolution) Principle: new modulation scheme (8PSK instead of GMSK) Performance: up to 384 kbps Implementation is yet to come (foreseen for 2003) EDGE might be a good alternative to 3G systems in certain areas or for operators who do not have 3G licences, although the 3G brings more in terms of new multimedia services. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 10
  • 1.Introduction/1.1 Context Let’s take some examples! Downloading a map (50 KBytes) GSM 42 s GPRS 8s EDGE 3 s UMTS 0.2 s Downloading a Word document (500 KBytes) GSM 7 mn GPRS 82 s EDGE 27 s UMTS 2s © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U A 2 1/2 minutes MP3 music file (2.4 MBytes) GSM GPRS EDGE UMTS 34 mn 7 mn 128 s 10 s Audio and Video streaming Streaming with all technologies except with GSM Page 11
  • 1.Introduction 1.1 Context 1.2 Standardization 1.3 UMTS Goals 1.4 UMTS technical overview © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 12
  • 1.Introduction/1.2 Standardization IMT-2000: definition IMT-2000 is a framework for third generation mobile systems (3G) which is scheduled to start service worldwide around the year 2000 subject to market considerations. IMT-2000 should use the frequencies around 2 GHz all over the world. IMT-2000 is defined by a set of interdependent ITU Recommendations*. IMT-2000 main requirements are : - wide range of high quality services - capability for multimedia applications - worldwide roaming capability - compatibility of services within IMT-2000 and with the fixed networks © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 13
  • 1.Introduction/1.2 Standardization IMT-2000: main participants Europe: ETSI Japan: ARIB USA: TIA, T1 South Korea: TTA China: CWTS ITU: International Telecommunication Union © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 14
  • 1.Introduction/1.2 Standardization IMT-2000: terrestrial radio interfaces IMT-TC (Time Code) TD-CDMA UMTS TDD IMT-DS (Direct Spread) W-CDMA UMTS FDD Evolved GSM Core Network © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U IMT-MC (Multi Carrier) CDMA2000 FDD MC Radio/Network Connection IMT-SC (Single Carrier) TDMA Single Carrier UWC-136 EDGE/ERAN IMT-FT (Frequency Time) TDMA Multi-Carrier DECT Evolved IS-41 Core Network Page 15
  • 1.Introduction/1.2 Standardization 2G terrestrial radio interfaces China : GSM US & Canada : W estern Europe: CDMA (13%) GSM GSM (12%) (87%) (100%) CDMA (49%) TDMA Japan: (39%) PDC (64%) (36%) Rest of the W orld : GSM (41%) CDMA CDMA (35%) TDMA (24%) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U 1999 Market Share: GSM 48 % CDMA 28 % TDMA 15 % PDC 9% Page 16
  • 1.Introduction/1.2 Standardization 3G terrestrial radio interfaces China : GSM US & Canada : GSM GSM (12%) EDGE (87%) UMTS W estern Europe: CDMA (49%) CDM A 2000 (100%) UMTS TDMA CDMA (13%) CDM A 2000 Japan: (39%) EDGE PDC (64%) UMTS Rest of the W orld : GSM (41%) UMTS CDMA (35%) CDM A 2000 UMTS TDMA (24%) EDGE IMT2000 CDMA (36%) CDM A 2000 UMTS 1999 Market Share: GSM 48 % UMTS CDMA 28 % CDM TDMA 15A % EDGE PDC 9% 2000 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 17
  • 1.Introduction/1.2 Standardization 3GPP: joint organization for UMTS standardization Affiliated organizations: ETSI (Europe) ARIB/TTC (Japan) T1 (USA) TTA (South Korea) CWTS (China) Other members involved: manufacturers and operators System Specification: Access Network WCDMA (UTRA FDD) TD-CDMA (UTRA TDD) Core Network Evolved GSM All-IP Releases defined for the system specifications: - Release 99 (called R3 as well) - Release R4 and R5 (previously known as Release 2000 or R’00) In the following material we will only refer to UMTS R99. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 18
  • 1.Introduction/1.2 Standardization 3GPP: TSG organization Project Co-ordination Group (PCG) TSG CN Core Network TSG RAN TSG SA Radio Access Networks Service and System TSG T Terminals Aspects TSG GERAN GSM EDGE Radio Access Network CN WG1 Mobility Management, Call Control, Session Management RAN WG1 Radio layer 1 specification SA WG1 Services T WG1 Mobile Terminal Conformance Testing GERAN WG1 Radio Aspects CN WG2 CAMEL RAN WG2 Radio Layer 2 & Radio Layer 3 RR specification SA WG2 Architecture T WG2 Mobile terminal services & capabilities GERAN WG2 Protocol Aspects CN WG3 Interworking with External Networks RAN WG3 Iub, Iur, Iu specification & UTRAN O&M requirements SA WG3 Security T WG3 Smart Card Application aspects GERAN WG3 Terminal Testing CN WG4 MAP/GTP /BCH/SS RAN WG4 Radio performance & Protocol aspects SA WG4 CODEC CN WG5 OSA Open Service Access © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U SA WG5 Telecom Management Page 19
  • 1.Introduction/1.2 Standardization 3GPP specifications Series_Id 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. Series_description Requirements Service Aspects Technical Realization Signaling Protocols (UE to network) UTRA aspects CODECs Data (reserved) Signaling Protocols (intra-fixed network) Program management User Identity Module O&M m Security Aspects ecs.ht ecs/sp sp Test specification p.org/ p Security algorithms ww.3g /w © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U http:/ Page 20
  • 1.Introduction/1.2 Standardization UMTS Roadmap EDGE Commercial introduction UMTS R99 commercial System UMTS R99 Field Trials GPRS implementation 2001 2002 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U UMTS R5 2003 2004 Page 21
  • 1.Introduction 1.1 Context 1.2 Standardization 1.3 UMTS Goals 1.4 UMTS technical overview © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 22
  • 1.Introduction/1.3 UMTS goals W UMTS? hy “UM will be a m o bile c o m m unic a tio n s y s te m tha t o ffe rs s ig nific a nt us e r TS be ne fits inc lud ing hig h-q ua lity wire le s s m ultim e d ia s e rvic e s to a c o nv e rg e nt ne two rk o f fix e d , c e llula r a nd s a te llite c o m p o ne nts . ” I will d e liv e r info rm a tio n d ire c tly to us e rs a nd p ro v id e the m with a c c e s s to t ne w a nd inno v a tiv e s e rv ic e s a nd a p p lic a tio ns . I will o ffe r m o bile p e rs o na liz e d c o m m unic a tio ns to the m a s s m a rke t t re g a rd le s s o f lo c a tio n, ne two rk a nd te rm ina l us e d . ” UMTS Forum 1997 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 23
  • 1.Introduction/1.3 UMTS goals UMTS vision Zone 4: Global Satellite Zone 3: Suburban Zone 2: Urban Zone 1: In-Building Macro-Cell MSS GSM © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Micro-Cell UTRA/ FDD Pico-Cell UTRA/ TDD Page 24
  • 1.Introduction 1.1 Context 1.2 Standardization 1.3 UMTS Goals 1.4 UMTS technical overview © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 25
  • 1.Introduction/1.4 UMTS technical overview UMTS general architecture PS networks CS networks (Internet…) (PSTN, ISDN..) CN Iu RAN Uu UE CN RAN UE Core Network Radio Access Network User Equipment © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Core network (CN) it provides support for the network features and telecommunication services. It is connected to external CS networks or PS networks. Radio Access network (RAN) it comprises roughly the functions specific to the access technique. 3 different RANs are foreseen: •UTRAN (UMTS Terrestrial RAN) •MSS (Mobile Satellite component) •BRAN (Broadband RAN) User Equipment (UE) It is the mobile phone. Page 26
  • 1.Introduction/1.4 UMTS technical overview UMTS Cellular System UMTS consists of a set of hierarchical cells, but the multiple access technique is completely different from GSM. GSM Users are separated in frequency (FDMA) and in time (TDMA) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U UMTS Users are separated with codes (CDMA) Page 27
  • 1.Introduction/1.4 UMTS technical overview UMTS duplex modes 5 MHz channel FDD mode Code and Frequency orthogonality f1 Up link f2 Do wnlink TDD mode Code and Time orthogonality © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U .. . 5 MHz channel Up link & Do wnlink .. . 15TS Page 28
  • 1.Introduction/1.4 UMTS technical overview UMTS Frequency allocations 2110 2170 FDD 1900 1920 TDD MSS 1980 FDD 2200 2010 MSS 2025 TDD Uplink Downlink FDD: Frequency Division Duplex TDD: Time Division Duplex MSS: Mobile Satellite System © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 29
  • 1.Introduction QUIZ! (1) Mark the following answers to the questions A to E by True or False. A. W hat are the limits of 2G systems like GSM? 1/ No security of communications 2/ No dynamical allocation of radio resources 3/ Mobility only in a small area 4/ Heavy mobile phones 5/ Limited offer of data services B. EDGE... 1/ is an evolution of GSM 2/ is sometimes considered as a 3G system 3/ is based on a new modulation scheme 4/ is supposed to reach a bit rate about 40 times greater than the GSM one © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 30
  • 1.Introduction QUIZ! (2) C. W hich of these radio interfaces belongs to IMT-2000? 1/ CDMA One 2/ UMTS FDD 3/ UMTS TDD 4/ CDMA 2000 5/ EDGE D. W hat is the organisation responsible for UMTS standardization? 1/ 3GPP 2/ 3GPP2 3/ ETSI 4/ ARIB 5/ CWTS E. W hat is the bandwidth of a CDMA carrier in UMTS? 1/ 200 kHz 2/ 1 MHz 3/ 5 MHz F. Are the following statements about UTMS duplex modes True or False? 1/ FDD is similar to the GSM duplex mode 2/ TDD use the same frequencies as FDD 3/ FDD is better suited for asymmetric traffic 4/ TDD will come later © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 31
  • 2. Services provided © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 32
  • 2. Services provided 2.1 UMTS service principles 2.2 UMTS Bearer services 2.3 Tele-services 2.4 UMTS Terminals © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 33
  • 2. Services provided/2.1 UMTS service principles W is a service? hat E.g speech, file transfer, emails... CN Node UTRAN TE/MT CN Gateway Teleservice External Bearer Service UMTS Bearer Service E.g data transfer at 9,6 kbps, in transparent mode, with turbocode ... TE Radio Access Bearer Service (RAB) Radio Bearer Service ... Iu Bearer Service CN Bearer Service Backbone Bearer Service ... Physical Radio Physical Bearer Service Bearer Service Uu © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Iu Page 34
  • 2. Services provided/2.1 UMTS service principles Teleservices Speech, emergency calls SMS Email Internet Access Mobile e-commerce Video Postcards Information and location based services New applications Tele-services and Bearer services “Instinctive” service Basic services Enhanced services New services to be provided by service providers (third party) UMTS Bearer services Large toolkit for all kinds of services © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 35
  • 2. Services provided/2.1 UMTS service principles Third party: service provider Tele-services will not be standardised so as to differentiate between operators and providers of applications. UMTS offer new opportunity for content and service providers Today’s 1:1 customer-operator relationship Tomorrow’s situation? Contracted Content providers Operator Contracted Service providers Contracted Service providers Operator © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 36
  • 2. Services provided/2.1 UMTS service principles Virtual Home Environment (VHE) The Virtual Home Environment (VHE) is an important portability concept of the 3G mobile systems. • it enables end users to bring with them their Personal Service Environment (PSE) whilst roaming between networks, • and also being independent of terminal used. • "same look and feel" wherever you are The PSE is defined in terms of one or more User Profiles (list of subscriptions, associated preferences, terminal interface preferences, …) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 37
  • 2. Services provided/2.1 UMTS service principles Service Architecture Service Layer Tele-services (terminal equipment functions, Operator transmission capabilities) Standardized interfaces Service Capability Features Service Capability Servers GSM/GPRS/UMTS Bearer Services CAMEL MExE SAT Network Layer Fixed VHE concept is based on the standard mechanisms of Service Capability Servers which allow Service Capability Features. The latter are carried through standard interfaces in order to support Tele-services adapted to the Service Capabilities of the network and user equipment. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 38
  • 2. Services provided/2.1 UMTS service principles Let’s Look for the nearest restaurant Choose your preferences: - type of restaurant: Fre nc h - type of payment: c re d it c a rd ... Restaurant Paul Bocuse 69660 Collonges-au-Mont-d'or This service is built from the following service capability features: call set-up & authorisation (CAMEL for services in roaming after authentication phase with SAT), Map display on the phone : SAT and MExE Call the restaurant by Push Service : MExE Reservation with VISA card number : secured transaction with MExE Billing of the service : CAMEL © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 39
  • 2. Services provided 2.1 UMTS service principles 2.2 UMTS Bearer services 2.3 Tele-services 2.4 UMTS Terminals © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 40
  • 2. Services provided/2.2 UMTS Bearer Services Bearer services characterization Bearer services are characterized by a set of end-to-end characteristics with requirements on QoS, always considered point-to-point. Bearer services provide the capability for information transfer between access points and involve only low layer functions. Each bearer service is characterized by its requirements: • transfer information: connection oriented or connectionless, traffic type (guaranteed/constant bit rate, non guaranteed/variable…), traffic characteristics (uni-directional, bi-directional, multicast…), priority • quality characteristics: maximum transfer delay, delay variation, bit error ratio, data rate. This set of requirements are called QoS parameters. Example : several active radio bearer services can be handled simultaneously by the same terminal equipment. Page 41 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U
  • 2. Services provided/2.2 UMTS Bearer Services Bearer QoS requirements • negotiable: QoS offer on demand • provide a wide range of QoS levels • dynamic behaviour: It shall be possible to negotiate (re-negotiate) the characteristics of a bearer service at session or connection establishment (during an on going session or connection). • support of asymmetric nature between uplink and downlink • supply of bearer services without wasting resources on the radio and network interfaces. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 42
  • 2. Services provided/2.2 UMTS Bearer Services Bearer Supported bit rates The only limiting factor for satisfying application requirements shall be the cumulative bit rate per mobile termination at a given instant in each radio environment: •At least 144 kbps in rural outdoor radio environment (with a maximum speed of 500 km/h) •At least 384 kbps in urban or suburban outdoor radio environments (with a maximum speed of 120 km/h) •At least 2048 kbps in indoor or low range outdoor radio environment (with a maximum speed of 10 km/h) Theses performances decrease: - when the speed of the user increases - when the load of the network increases © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 43
  • 2. Services provided 2.1 UMTS service principles 2.2 UMTS Bearer services 2.3 Tele-services 2.4 UMTS Terminals © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 44
  • 2. Services provided/2.3 Tele-services Typology Media Always-on • • • • • Directories Mobile Office • • • • • • Voice (!) E-mail Agenda IntraNet/InterNet Corporate Applications Database Access • Yellow/White Pages • I rna tio na l Dire c to rie s nte • Operator Services Games (Hangman, Poker, Quiz, …) Screen Saver Ring Tone Horoscope Biorhythm Music • Downloading of music files or video clips Transportation • Flight/train Schedule • reservation Vertical application • • • • Fun Traffic Management Automation Mobile branches Health News (general/ specific) • • • • • • • • International/National News Local News Sport News Weather Lottery Results Finance News Stock Quotes Exchange Rates Location services • Traffic Conditions • Itineraries • Nearest Restaurant, Cinema, Chemist, Parking;, ATM ... M-commerce Non physical • • • • • • © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U on-line Banking Ticketing Auction Gambling Best Price e-Book Physical • on-line shopping • on-line food Page 45
  • 2. Services provided/2.3 Tele-services QoS classes 4 classes have been identified: conversational + Delay sensitive - • AMR speech service • Video telephony – CS: H324 – PS: H323 streaming interactive • Web-browsing • location based services background Data Integrity sensitive + • e-mail delivery • SMS ... © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 46
  • 2. Services provided/2.3 Tele-services Performance QoS of teleservices depends not only on UMTS network, but also on applications, terminals and external networks. From a user’s perspective it is more relevant to speak of delay rather than bit rate: Error tolerant Conversational Streaming audio Voice messaging and video voice and video FTP, still image, E-commerce, Error Telnet, WWW browsing paging intolerant interactive games Conversational delay <<1 sec © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Streaming delay<1 sec Interactive delay <10 sec Fax E-mail arrival notification Background delay >10 sec Page 47
  • 2. Services provided/2.3 Tele-services Defining charging principles • How will billing be performed: by time? by volume? by number of connections? • If billing is performed by volume, what will be an easy way to explain to the customer what a “1 Mbyte of data” is? • What will happen in case of handover between GSM and UMTS? • What about roaming? Prepaid services? • QoS depends directly on the load of the network. A trade-off must be found between users. Customers who pay more might have higher priority or better QoS (depending of the operator’s strategies). Billing for a given service might depend on the QoS. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 48
  • 2. Services provided/2.3 Teleservices Location based services Teleservices will depend on the strategy and on the imagination of operators and content providers. The key point is likely to be a fast access to information and an appropriate filtering of the user location data. the UMTS killer application is likely be a location based service Example of location based services : look for an hotel, consult yellow pages, get local traffic situation or weather report,... Limitation: location information could be a risk for privacy. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 49
  • 2. Services provided 2.1 UMTS service principles 2.2 UMTS Bearer services 2.3 Tele-services 2.4 UMTS Terminals © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 50
  • 2. Services provided/2.4 UMTS terminals User Equipement (UE) Cu interface UICC USIM1 USIM2 GSM access SIM Mobile Equipment GSM/GPR S terminal (ME) User Equipment (UE) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 51
  • 2. Services provided/2.4 UMTS terminals Range of terminals There will be a wide range of terminals depending of the type of application (speech, video, games, dual...), the mode (UMTS/GSM, UMTS/DECT...) Integrated approach: 1 handset able to perform all functions. Most of the concept phones today. Distributed approach: 1 handset for voice & WAP, or voice only and a Bluetooth connection to other devices (headset, camera...). New interfaces Automotive / Telematics PS G Data / IT E-Commerce Consumer Electronics Image © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Domestic Games Audio Page 52
  • 2. Services provided QUIZ! A. True or False? The tele-services... 1/ are used for example to make a call, to access yellow pages, on-line banking... 2/ are mapped on bearer services 3/ will be standardized by 3GPP B. True of False? The VHE... 1/ is a portability concept of 3G mobile systems 2/ will enable to keep the same environment when roaming between mobile and fixed networks 3/ will be adapted to the terminal capabilities 4/ will use proprietary interfaces © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 53
  • 2. Services provided QUIZ! C. True or False? A bearer service can support for one user: 1/ 2 Mbps at a speed of 120 km/h 2/ 2 Mbps in a high loaded cell 3/ 2 Mbps at 3 km away from the base station 4/ Asymmetric traffic 5/ Variable traffic D. True or False? Location based services... 1/ are services only available in some areas (city centers...) 2/ are services related to the location of the user 3/ can locate the mobile phone with an accuracy of about 50 m © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 54
  • 2. Services provided QUIZ! E. True or False? A UICC (UMTS integrated Circuit Card)... 1/ has the same size as a GSM SIM card 2/ can not be used in a GSM terminal 3/ can be used in an UMTS terminal and provide access to GSM network 4/ is linked with the UMTS terminal via a proprietary interface 5/ may provide access to UMTS networks of different operators F. UMTS services have been announced to come later than initially scheduled because of non availability of UMTS terminals in volume: can you find some reasons which makes it quite complex to design UMTS terminals? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 55
  • 3. UMTS System Description © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 56
  • 3. UMTS System Description 3 views of the system Protocol architecture Logical architecture Pro to c o l s ta c ks Entitie s Be a re rs Call scenario © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 57
  • 3. UMTS System Description Pro to c o l s ta c ks Entitie s 3.1 Logical architecture Be a re rs 3.2 Protocol architecture 3.3 Call scenario © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 58
  • 3. UMTS System Descript./3.1 UMTS logical architecture UMTS logical Architecture CN Core Network CS-Service Domain PS-Service Domain Iu-CS IU Iu-PS Iu-PS RNS RNS Iur RNC UTRA N UU Iu-CS Iu-reference point Iub Node_B Node B Iub Node B RNC Iub Node B Iub Node B Uu-reference point UE © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 59
  • 3. UMTS System Descript./3.1 UMTS logical architecture CN logical architecture UMTS Core Network for Release 99 2G/3G MSC PLM N PS TN / I DN S 2G/3G GMSC A GSM BSS BSC EIR Gb HLR AuC VHE Iu (CS) UTRAN RNC Iu (PS) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U 2G/3G SGSN I Ba c kbo ne 2G/3G P GGSN Ex te rna l I N two rk P e Page 60
  • 3. UMTS System Descript./3.1 UMTS logical architecture RNS UTRAN logical Architecture RNS Iur RNC Iub Node_B Node B Iub Node B RNC Iub Node B Iub Node B RNC It is the intelligent part of the UTRAN: - radio resource management (code allocation, congestion control, admission control) - radio mobility management - macro-diversity handling (soft HO) - control of Node-Bs Node-B A Node-B can be composed of several cells and performs: - radio transmission handling - macro-diversity handling (softer HO) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 61
  • 3. UMTS System Descript./3.1 UMTS logical architecture Soft Handover (1) Core Network I u I u I ur S RNC1 DRNC2 S I ub I ub I ub NodeB1 1 I ub NodeB2 NodeB3 NodeB4 2 3 4 5 6 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 62
  • 3. UMTS System Descript./3.1 UMTS logical architecture Soft Handover (2) The role of an RNC (Serving or Drift) is on a per connection basis between a UE and the UTRAN: Serving RNC: provide Iu UE-CN connection Drift RNC: supports Serving RNC by providing radio resources The recombination of the signal is performed in Serving RNC (in Node B for softer HO) and in UE using a RAKE receiver. Soft HO is highly recommended in UMTS system: about 30 to 40% of mobiles are in macro-diversity mode in IS-95. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 63
  • 3. UMTS System Descript./3.1 UMTS logical architecture UMTS logical Interfaces Open Interfaces The functional split for the UMTS components (UE, Node-B, RNC...) are clearly specified, but the internal architecture and implementation issues are left open (it is up to the manufacturer). However all the interfaces (Cu, Uu, Iub, Iur, Iu-CS, Iu-Ps) have been defined in such a detailed level that the equipment at the endpoints can be from different manufacturers. “Open Interfaces” aim at motivating competition between manufacturers. Physical implementation of Iu interfaces Each Iu Interface may be implemented on any physical connection using any transport technology. ATM will be provided in the R99 release and IP is foreseen in further releases © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 64
  • 3. UMTS System Description Pro to c o l s ta c ks Entitie s 3.1 Logical architecture Be a re rs 3.2 Protocol architecture 3.3 Call scenario © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 65
  • 3. UMTS System Descri./3.2 UMTS protocol Access stratum and Non Access Stratum architecture N n-A c e s s Stra tum (N S) o c A Iu Radio Protocols Protocols (2) (1) Radio Protocols (1) Iu Protocols (2) A c e s s Stra tum c (A S) UE Uu UTRAN CN Iu SAP Interchanges between entities is applied on a peer-to-peer principle. Each entity provides services to entities of upper layers through Service Access Points (SAP). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 66
  • 3. UMTS System Descri./3.2 UMTS protocol architecture Non Access Stratum CS traffic CM/ MM CS traffic PS traffic CM/ MM SM/ GMM Iu Protocols NAS A S Uu Radio Protocols UE Radio Protocols Iu Protocols IuCS MSC SM/ GMM UTRAN PS traffic Iu Protocols Iu-PS SGSN © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 67
  • 3. UMTS System Descri./3.2 UMTS protocol architecture 1 2 4 Access Stratum: radio protocols 4. Us e r a uthe ntic a tio n (N S s ig na lling ) A 2 . We b bro ws ing (fro m /to I u-PS) 3 . Lo c a l we a the r 1 . Sp e e c h (fro m /to I u-CS) fo re c a s t (SM S Ce ll 3 N NA O CCESS STRA TUM(N S) A Bro a d c a s t ) ACCE SS ATUM(AS S TR ) RRC 5. I nitia l a c c e s s (RRC Co nne c tio n Es ta blis hm e nt) RRC PDCP BMC RLC MAC RLC MAC Phys Phys UE Uu © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Iu protocols Node B Iu protocols Iub ne pla ol ne ntr pla Co er Us PDCP BMC RNC Page 68
  • 3. UMTS System Descri./3.2 UMTS protocol architecture Node-B Iub N P BA Iu-CS RNC RN P SA Radio Network Layer Application Protocol: - N P for Iub BA - RN P for Iur SA - RA A for Iu-CS N P and Iu-PS © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Transport Iur SGSN Iu-PS Control Plane User Plane Application Protocol Transport Network User Plane Data Stream(s) Transport Network Control Plane Transport Network User Plane ALCAP Network Layer MSC RA A N P RNC The same general protocol model is applied for all Iu interfaces: Access Stratum: Iu protocols Signaling Bearer(s) Signaling Bearer(s) Data Bearer(s) Physical Layer Page 69
  • 3. UMTS System Description Pro to c o l s ta c ks Entitie s 3.1 Logical architecture Be a re rs 3.2 Protocol architecture 3.3 Call scenario © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 70
  • 3. UMTS System Description/3.3 Call Scenario Radio Access Bearer (RAB) UMTS Bearers CN-CS A R B R B A UMTS Bearer UTRAN UE UMTS Bearer R A B R A B UMTS bearer services CN-PS Radio Bearers Iu Bearers RABs (mapped on Radio & Iu Bearers) “The RAB provides confidential transport of signaling and user data between UE and CN with the appropriate QoS”. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 71
  • 3. UMTS System Description/3.3 Call Scenario Establishment of a call Inside the UTRAN No more distinction between CS and PS part: all data are mapped on RAB. But the RAB characteristics (delay, bit rate…) may not be the same for CS and PS part. UTRAN has the total freedom to configure the radio bearers according to the required RAB attributes (ie QoS). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 72
  • 3. UMTS System Description/3.3 Call Scenario Example : CS call establishment UE UTRAN Uu Iu CN Connection to UTRAN (RRC Connection establishment) Request for service (RRC) (RANAP) Authentication and Ciphering / Integrity Setup Establishment of Resources (RAB + Radio Bearer) Alert and Connect © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 73
  • 3. UMTS System Description QUIZ! A. Put the correct words in the spaces on the figure below ... ... CS networks (PSTN, ISDN) ... ... ... ... ... ... ... ... PS networks (internet) ... ... ... © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U ... ... Page 74
  • 3. UMTS System Description Quiz! B. W hich of the following statements concerning the soft(er) handover is true of false? 1/ a soft(er) HO consists of two or more simultaneous radio links between the UE and the UTRAN 2/ a soft HO is under the control of the Drift RNC 3/ a softer HO is performed by Node-B C. W here is performed the radio mobility management? 1/ in the CN 2/ at the RNC 3/ at the Node-B D. According to the norm, can the RNC from a given manufacturer be compatible with: 1/ the CN of another manufacturer? 2/ the RNC of another manufacturer? 3/ the Node-B of another manufacturer? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 75
  • 4. WCDMA for UMTS © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 76
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 77
  • 4. WCDMA for UMTS/ 4.1 Context From military to civil modern radio-communications Early 70’s CDMA developed for military field for its great qualities of privacy (low probability interception, interference rejection) 1996 CDMA commercial launch in the US This system called IS-95 or cdmaOne was developed by Qualcomm and has reached 50 million subscribers worldwide 2000 IMT-2000 has selected three CDMA radio interfaces: - WCDMA (UTRA FDD) - TD-CDMA (UTRA TDD) - CDMA 2000 In the following material we will only refer to W CDMA (UTRA FDD) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 78
  • 4. WCDMA for UMTS/ 4.1 Context W CDMA? hy CDMA is very attractive: • Better spectrum efficiency than 2G systems • Suitable for all type of services (circuit, packet) and for multi-services • Enhanced privacy • Evolutionary (linked with progress in signal processing field) BUT: • Complex system: not easy to configure and to manage • Unstable in case of congestion © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 79
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 80
  • 4. WCDMA for UMTS/ 4.2 Spread Spectrum Modulation A code as a shell against noise Noise Spreading Transmitter Radio channel Despreading Receiver The letter ‘A’ represents the signal to transmit over the radio interface. At the transmitter the height (ie the power) of ‘A’ is spread, while a color (i.e a code) is added to ‘A’. At the receiver ‘A’ can be retrieved with knowledge of the code, even if the power of the received signal is below the power of noise due to the radio channel. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 81
  • 4. WCDMA for UMTS/ 4.2 Spread Spectrum Modulation P P f Spreading Radio channel Spectrum spreading P P N is e o le v e l f f f De-spreading At the transmitter the signal is multiplied by a code which spreads the signal over a wide bandwidth while decreasing the power (per unit of spectrum). At the receiver it is possible to retrieve the wanted signal by multiplying the received signal by the same code: you get a peak of correlation, while the noise level due to the radio channel remains the same, because this is not correlated with the code. The spectrum spreading permits transmission of a signal below the noise level and makes the signal very hard to detect. Spectrum spreading makes CDMA very secure. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 82
  • 4. WCDMA for UMTS/ 4.2 Spread Spectrum Modulation Transmission Chain Air Interface NB-Signal WB-Signal WB-Signal NB-Signal Data Data Modulator Code sequence Demodulator Code Sequence The narrowband data signal is multiplied bit per bit by a code sequence: it is known as “chipping”. The chip rate of this code sequence is much higher than the bit rate of the data signal: it produces a wideband signal, also called spread signal. At the receiver the same code sequence in phase should be used to retrieve the original data signal. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 83
  • 4. WCDMA for UMTS/ 4.2 Spread Spectrum Modulation Signal Spreading Code Tx signal 1 1111 0101 0101 0 0000 0101 1010 0 0000 0101 1010 Rx signal Code Despreading Signal 0101 0101 1111 1 1010 0101 0000 0 Spreading factor (bits) (chips) 1010 0101 0000 0 Radio channel (In this case, each bit of the signal is spread over 4 chips. The spreading factor is 4) Spreading makes CDMA adequate for services with variable bit rates. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 84
  • 4. WCDMA for UMTS/ 4.2 Spread Spectrum Modulation Processing Gain P W  Processing Gain = 10 Log 10   Rb  Processing Gain De-spreading W Rb f The Processing Gain is the gain you have at the receiver by the despreading of the signal (peak of correlation). It enables transmission of the signal below the noise level. A high bit rate signal needs more power to cross the noise level by despreading. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 85
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 86
  • 4. WCDMA for UMTS/ 4.3 Code Division Multiple Access One-cell reuse The area is divided into cells, but the entire bandwidth is reused in each cell (frequency reuse of one) > Inter-cell interference > Cell orthogonality is achieved by codes The entire bandwidth is used by each user at the same time > Intra-cell interference > User orthogonality is achieved by codes © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 87
  • 4. WCDMA for UMTS/ 4.3 Code Division Multiple Access Multiple access (1) Spreading 1 Transmitter 1 Spreading 2 Radio Channel Spreading1 Receiver The receiver aims at receiving Transmitter 1 only. Transmitter 2 All the users transmit on the same 5 MHz carrier at the same time and interfere with each over. At the receiver the users can be separated by means of (quasi-)orthogonal codes. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 88
  • 4. WCDMA for UMTS/ 4.3 Code Division Multiple Access Multiple access (2) Spreading 1 Transmitter 1 Spreading 2 Radio Channel Spreading1 Receiver The receiver aims at receiving Transmitter 1 only. Transmitter 2 If a user transmits with a very high power, it will be impossible for the receiver to decode the wanted signal (despite use of quasi-orthogonal codes) CDMA is unstable by nature and requires accurate power control. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 89
  • 4. WCDMA for UMTS/ 4.3 Code Division Multiple Access Spreading: Channelization and scrambling cch1 air interface cch 2 cscrambling M d ula to r o cch 3 The channelization code (or spreading code) is signal-specific: the code length is chosen according to the bit rate of the signal. The scrambling code is equipment-specific. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 90
  • 4. WCDMA for UMTS/ 4.3 Code Division Multiple Access Channelization codes (spreading codes) C C ch,1,0 = (1,1,-1,-1) ch,4,2 = (1,-1,1,-1) C C ch,2,0 ch,4,1 C C ch,4,0 =(1,1,1,1) ch,4,3 = (1,-1,-1,1) = (1,1) The code tree is shared by several users (usually one code tree per cell) = (1) C SF = 1 ch,2,1 = (1,-1) SF = 2 SF = 4 SF = 8 The channelization codes are OVSF (Orthogonal Variable Spreading Factor) codes: • their length is equal to the spreading factor of the signal: they can match variable bit rates on a frame-by-frame basis. • orthogonality enables to separate physical channels: UL: separation of physical channels from the same terminal DL: separation of physical channels to different users within one cell © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 91
  • 4. WCDMA for UMTS/ 4.3 Code Division Multiple Access Scrambling codes The scrambling codes provide separation between equipment: • UL: separation of terminals No need for code planning (millions of codes!) There are 214 long and 214 short scrambling codes in uplink • DL: separation of cells Need for code planning between cells (but trivial task) There are only long scrambling codes in downlink (512 to limit the code identification during cell search procedure) The long scrambling codes are truncated to the 10 ms frame length. Only one DL scrambling code should be used within a cell. Another scrambling code may be introduced in one cell if necessary (example : shortage of channelization code), but orthogonality between users will be degraded. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 92
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 93
  • 4. WCDMA for UMTS/ 4.4 Rake Receiver Rake Receiver principle (1) In a CDMA system there is a single carrier which contains all user signals. Decoding of all these signals by one receiver is only a question of signal processing capacity. A Rake receiver is capable to decode several signals simultaneously in the so called “fingers” and to combine them in order to improve the quality of the signal or to get several services at the same time. A Rake receiver is implemented in mobile phones and in base stations. A Rake receiver can provide: - multi-service (via handling of multiple physical channels that are carrying the services) - soft handover - path diversity © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 94
  • 4. WCDMA for UMTS/ 4.4 Rake Receiver Rake receiver principle (2) Delay Adjustment Multi-code signal 1 st Fing e r Delay 1 2 nd Fing e r Delay 2 3 rd Fing e r Data 1 Code Sequence 1 Code Sequence 2 Data 2 Delay 3 Code Sequence 2 or 3 The components of the multi-code signal are demodulated in parallel each in one “finger” of the Rake Receiver. The outputs of the fingers: • can provide independent data signals • can be combined to provide a better data signal(s) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 95
  • 4. WCDMA for UMTS/ 4.4 Rake Receiver Rake receiver and multi-service Despreading 1 Spreading 1 Spreading 2 Radio Channel Transmitter Despreading 2 Multimedia receiver As a first approach, we can say: One service, one code! (*) >> Which codes make it possible to separate the two signals at the receiver? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 96
  • 4. WCDMA for UMTS/ 4.4 Rake Receiver Rake Receiver and soft handover Spreading 1 Base station 1 Spreading 2 Base Station 2 Radio Channel Despreading 1&2 Mobile phone >> Which codes make it possible to separate the two signals at the receiver? Soft handover is possible, because the two mobile stations use the same frequency band. The mobile phone need only one transmission chain to decode both simultaneously. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 97
  • 4. WCDMA for UMTS/ 4.4 Rake Receiver Rake Receiver and path diversity (1) Natural obstacles (buildings, hills…) cause reflections, diffractions and scattering and consequently multipath propagation. The delay dispersion depends on the environment and is typically: • 1 µs (300 m) in urban areas • 20 µs (6000 m) in hilly areas The delay dispersion should be compared with the chip duration 0,26 µs (78 m) of the CDMA system. If the delay dispersion is greater than the chip duration, the multipath components of the signal can be separated by a Rake Receiver. In this case, CDMA can take advantage of multipath propagation. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 98
  • 4. WCDMA for UMTS/ 4.4 Rake Receiver Rake Receiver and path diversity (2) Direct path Despreading Spreading Transmitter Reflected path Dispersion <Chip duration The Rake Receiver cannot provide path diversity. Receiver >> Which codes make it possible to separate the two signals at the receiver? Direct path Spreading Transmitter Despreading Reflected path Receiver Dispersion > Chip duration The Rake Receiver can provide path diversity to improve the quality of the signal. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 99
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 100
  • 4. WCDMA for UMTS/ 4.5 Power Control W Power Control? hy MS2 MS1 Node B Near-Far Problem on the uplink way an overpowered mobile phone near the base station can jam any other mobile phones far from the base station. > Need for very efficient and very fast Power Control on UL > Power Control is also used in DL to reduce interference and consequently to increase the system capacity. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 101
  • 4. WCDMA for UMTS/ 4.5 Power Control Open Loop Open loop power control 1 Node B 2 If UE receives a STRONG DL signal, then UE will speak low. 1 Node B 2 If UE receives a weak DL signal, then UE will speak LOUD. Problem: fading is not correlated on UL and DL due to separation of UL and DL band. Open loop Power Control is inaccurate. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 102
  • 4. WCDMA for UMTS/ 4.5 Power Control Closed Loop Closed loop power control ”Power down” SIR estimation RNC SIR target Node B SIR estimation SIR estimation ”Power down” ”Power up” ”Power ...” SIR estimation ... The Node-B controls the power of the UE (and vice versa) by performing a SIR estimation (inner loop). The RNC controls parameters of the SIR estimation (outer loop). This SIR estimation is performed each 0,66 ms (1500 Hz command rate). Closed loop Power Control is very fast. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 103
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 104
  • 4. WCDMA for UMTS/ 4.6 Soft Handover Soft Handover (1) RNC Node B Node B Node B Soft HO © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Softer HO Page 105
  • 4. WCDMA for UMTS/ 4.6 Soft Handover Soft Handover (2) Why do we need soft HO? Imagine that a UE penetrates from one cell deeply into an adjacent cell: > it may cause near-far problem > hard HO is not a good solution, because of the need for the hysteresis mechanism Additional resources due to soft HO: - Additional rake receiver in Node-B - Additional Rake Fingers in UE - Additional transmission links between Node-Bs and RNCs Soft HO provides Diversity (also called Macro-Diversity), but requires more network resource. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 106
  • 4. WCDMA for UMTS/ 4.6 Soft Handover Soft Handover (3) Soft Handover execution: Soft Handover is executed by means of the following procedures • Radio Link Addition (FDD soft-add); • Radio Link Removal (FDD soft-drop); • Combined Radio Link Addition and Removal. The cell to be added to the active set needs to have information forwarded by the RNC: • Connection parameters (coding scheme, layer 2 information, …) • UE ID and uplink scrambling code, • Timing information from UE The UE needs to get the following information • Channelization & scrambling codes to be used • Relative timing information (Timing offset based on CPICH synchro) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 107
  • 4. WCDMA for UMTS 4.1 Context 4.2 Spread Spectrum modulation 4.3 Code Division Multiple Access 4.4 Rake Receiver 4.5 Power Control 4.6 Soft Handover 4.7 Typical coverage and capacity values © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 108
  • 4. WCDMA for UMTS/ 4.7 Typical coverage and capacity values Radio dimensioning process: W hat’s new? Market perspective Mobile data market forecast Marketing inputs Multi-service environment Voice+data Variable bit rate Different QoS Asymmetric traffic New radio technology W-CDMA Capacity Coverage © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Quality Page 109
  • 4. WCDMA for UMTS/ 4.7 Typical coverage and capacity values Concentric coverage The coverage is determined by the uplink range, because the transmission power of the terminal is much lower than that of the base station. R1 R2 UE Transmit Power R3 21 dBm (126 mW) 24 dBm (251 mW) Service in suburban area Cell radius (uplink limited) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Speech 12 kbps R1 ≈ 3 km Packet data 144 kbps R2 ≈ 2 km Packet data 384 kbps R3 ≈ 1,5 km Page 110
  • 4. WCDMA for UMTS/ 4.7 Typical coverage and capacity values W of improving coverage ays AMR speech Codec it enables to switch to a lower bit rate if the mobile is moving out of the cell coverage area: it is a trade-off between quality and coverage. Multipath diversity it consists of combining the different paths of a signal (due to reflections, diffractions or scattering) by using a Rake Receiver. Multipath diversity is very efficient with W -CDMA. Soft(er) handover the transmission from the mobile is received by two or more base stations. Receive antenna diversity the base station collects the signal on two uncorrelated branches. It can be obtained by space or polarization diversity. Base stations algorithms e.g. accuracy of SIR estimation in power control process © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 111
  • 4. WCDMA for UMTS/ 4.7 Typical coverage and capacity values Soft capacity The capacity is determined by the downlink direction, because: - better receiver techniques can be used in the base station than in the mobile station (but requiring more CPU power). - the downlink capacity is expected to be more important than the uplink capacity because of asymmetric traffic. The downlink capacity has two limitations: - the amount of interference in the air interface Adjacent cells share part of the same interference: there is an additional capacity in a cell, if the number of users in the neighboring cells is smaller. - the loss of code orthogonality The downlink codes originate from a single point and can be synchronized. But, after transmission over multipath channel, part of orthogonality is lost. It is a soft capacity, because it is not limited by the hardware equipment. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 112
  • 4. WCDMA for UMTS/ 4.7 Typical coverage and capacity values Parameters influencing capacity The capacity depends on: - the radio environment (rural, suburban, indoor) - the terminal speeds - the distribution of the terminals - the load of the cell: trade-off capacity/coverage (breathing cells) High loaded cell High DL interference level DL data throughput 660 kbps (per carrier per sector) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U High loaded cell Low DL interference level DL data throughput 1440 kbps (per carrier per sector) Page 113
  • 4. WCDMA for UMTS QUIZ! A. True or False? Spreading... 1/ consists of increasing the power while decreasing the frequency bandwidth 2/ allows to transmit a signal with a S/N (Signal-to-Noise ratio) smaller than one 3/ enables to retrieve the coded signal at the receiver by using the same code in phase 4/ is used in FDMA system B. Signal 1 has a bit rate of 12 kbps and a coding rate of 1/ signal 2 has a bit rate of 384 kbps 3, and a coding rate of 1/ 2: 1/ Which spreading factor should be chosen for each of these signals? 2/ What is the processing gain for each of these signals? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 114
  • 4. WCDMA for UMTS QUIZ! C. True of false? W CDMA... 1/ is also called UMTS FDD or UTRA FDD 2/ uses a 1 MHz bandwidth carrier 3/ has a chip rate of 3,84 Mchips/s D. How many carriers are there per operator for W CDMA? 1/ 124 carriers 2/ 62 carriers 3/ 1 to 3 according to the country E. True or false? A Rake Receiver 1/ can separate simultaneously two signals only if their codes are perfectly orthogonal 2/ can separate simultaneously several signals of 2 different WCDMA carriers 3/ can take advantage of multipath propagation © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 115
  • 4. WCDMA for UMTS QUIZ! F. True or false? In W CDMA, power control 1/ is used in uplink and in downlink 2/ is crucial in downlink because of near-far problem 3/ is composed of the open loop and the closed loop 4/ may be performed each WCDMA time slot (1500 Hz command rate) G. True or false? Soft handover... 1/ is highly desirable in WCDMA 2/ require use of more frequencies 3/ require use of more power in uplink 4/ require additional signal processing equipment such as Rake Receiver 5/ require additional transmission links © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 116
  • 5. UMTS Terrestrial Radio Access Network (FDD mode, Release 1999) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 117
  • 5. UTRAN UTRAN role and principles Layer 3 Layer 2 Layer 1 UE Uu Node B I ub RNC CN • To transfer traffic and control channels between UE and CN - Common handling of packet-switched and circuit-switched data - Protection of the user data on the air interface (providing of ciphering) - Independence from the applied transport technology on the Iu interface • To manage the radio mobility of the user Full control of UE radio mobility with the use of the Iur interface which makes it possible to perform soft HO even with 2 cells/Node-Bs belonging to different RNCs. • To make efficient use of limited radio resources Support of WCDMA specific Radio Resource Management (RRM) algorithms. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 118
  • 5. UTRAN Layer 3 Layer 2 Layer 1 UE 5.1 From Radio Bearers to transport channels 5.2 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signalling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 RNC Radio Protocols 5.3 Node B Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 119
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Situation CN Node UTRAN UE CN Gateway UE Teleservice External Bearer Service UMTS Bearer Service Radio Access Bearer Service (RAB) Radio Bearer Service ... Radio Physical Bearer Service Uu © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Iu Bearer Service CN Bearer Service Backbone Bearer Service ... Physical Bearer Service Iu Page 120
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Radio Bearers, logical and transport channels Control plane NAS signalling RRC Sig na lling Ra d io Be a re rs User plane W browsing eb Telephony speech RRC connection establishment SMS Cell Broadcast PDCP Us e r p la ne Ra d io BMCBe a re rs RLC Co ntro l Lo g ic a l Cha nne l s MAC Tra ns p o rt Cha nne ls Phys. UTRAN © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Tra ffic Lo g ic a l Cha nne ls (Iur)/Iub/Uu ... MAC Tra ns p o rt Cha nne ls Phys. UE Page 121
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Radio Bearers Signalling Radio Bearers (SRB) SRBs can carry: - layer 3 signalling (e.g. RRC connection establishment) - NAS signalling (e.g location update) There can be up to 4 SRBs per RRC connection (one UE has one RRC connection when connected to the UTRAN). User Plane Radio Bearers RABs are mapped on user plane RBs. One RAB can be divided on RAB sub-flows and each sub-flow is mapped on one user plane RB. e.g the AMR codec encodes/decodes speech into/from three sub-flows; each sub-flow can have its own channel coding. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 122
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Logical Channels (1) Control Channels (CCH) Broadcast Control Channel (BCCH) Paging Control Channel (PCCH) UTRAN Common Control Channel (CCCH) Dedicated Control Channel (DCCH) Traffic Channels (TCH) Dedicated Traffic Channel (DTCH) Common Traffic Channel (CTCH) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 123
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Logical UL ( ) / DL ( ) Channels (2) Wha t typ e of inform a tion ? BCCH System control information e.g cell identity, uplink interference level PCCH P aging information e.g CN originated call when the network does not know the location cell of the UE CCCH Control information e.g initial access (RRC connection request), cell update D CCH Control information (but the UE must have a RRC connection) e.g radio bearer setup, measurement reports, HO D TCH T raffic information dedicated to one UE e.g speech, fax, web browsing CTCH T raffic information to all or a group of UEs e.g SMS-Cell Broadcast © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 124
  • 5. UTRAN/5.1 From Radio Bearers to transport channels W hy Transport Channels? A transport channel offers a flexible pattern to arrange information on any service-specific rate, delay or coding before mapping it on a physical channel: • it provides flexibility in traffic variation • it enables multiplexing of transport channels on the same physical channel Transport channels provide an efficient and fast flexibility in radio resource management. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 125
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Structure of a Transport Channel (1) Transport Block: basic unit exchanged over transport channels. Transport Format (TF): it may be changed every TTI. Each TF must belong to the Transport Format Set (TFS) of the transport channel 168 360 bits 168 168 168 360 168 168 168 10 ms 10 ms Time Transmission Interval (TTI): periodicity at which a Transport Block Set is transferred by the physical layer on the radio interface © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U 10 ms 10 ms >> The system delivers one Transport Block Set to the physical layer every TTI: what is the delivery bit rate of the transport blocks to the physical layer during the first TTI? Page 126
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Structure of a Transport Channel (2) Transport Format (TF) • Semi-static part (can be changed, but long process) Transmission Time Interval (TTI), Coding scheme... • Dynamic part (may be changed easily) Size of transport block, Number of transport blocks per TTI Transport Format Set (TFS) It is the set of allowed Transport Formats for a transport channel, which is assigned by RRC protocol entity to MAC protocol entity. MAC chooses TF among TFS. MAC may choose another TF every TTI without interchanging with RRC protocol (fast radio resource control). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 127
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Example 576 bits 576 576 576 576 576 576 576 576 40 ms Sta tic Pa rt TTI Coding scheme CRC ? T urbo coding, coding rate= 1/ 3 16 bits D yna m ic Pa rt T ransport Block Size T ransport Block Size Set ? 576*B (B= 0,1,2,3,4) 1. Complete the table 2. What is the delivery bit rate of the transport blocks to the physical layer during the first TTI? 3. How many Transport Format(s) may be chosen for this transport channel? 4. Can you imagine why the transfer has been interrupted during the third TTI? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 128
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Transport Channels Common Channels Broadcast Channel (BCH) Paging Channel (PCH) UTRAN Forward Access Channel (FACH) Downlink Shared Channel (DSCH) Random Access Channel (RACH) Common Packet Channel (CPCH) Dedicated Channels Dedicated Channel (DCH) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 129
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Common Transport Channels (1) BCH: Broadcast Channel A downlink transport channel that is used to carry BCCH. The BCH is always transmitted with high power over the entire cell with a low fixed bit rate. >> The BCH is the only transport channel with a single transport format (no flexibility). Can you explain why? PCH: Paging Channel A downlink transport channel that is used to carry PCCH. It is always transmitted over the entire cell. >> Is it possible to carry all types of information on the PCH? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 130
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Common Transport Channels (2) FACH: Forward Access Channel A downlink transport channel that is used to carry control information. It may also carry short users packets. The FACH is transmitted over the entire cell or over only a part of the cell using beam-forming antennas. The FACH uses open loop power control (slow power control). >> In which case is it interesting to use beam-forming antennas? would it also be relevant to implement this feature for PCH? RACH: Random Access Channel An uplink transport channel that is used to carry control information from the mobile especially at the initial access. It may also carry short user packets. The RACH is always received from the entire cell and is characterized by a limited size data field, a collision risk and by the use of open loop power control (slow power control). >> Why is it interesting to carry short user packets on RACH in spite of limited data field and collision risk (instead of using a dedicated channel)? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 131
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Common Transport Channels (3) DSCH: Downlink Shared Channel A downlink transport channel shared by several UEs to carry dedicated control or user information. When a UE is using the DSCH, it always has an associated DCH, which provides power control. CPCH: Common Packet Channel An uplink transport channel that is used to carry long user data packets and control packets. It is a contention based random access channel. It is always associated with a dedicated channel on the downlink, which provides power control. ⇒ Tra ns fe r o f s ig na lling a nd tra ffic o n a s ha re d ba s is © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 132
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Dedicated Transport Channels DCH: Dedicated Channel A downlink or uplink transport channel that is used to carry user or control information. It is characterized by features such as fast rate change (on a frame-by-frame basis), fast power control, use of beam-forming and support of soft HO. > > Two fe a ture s a re o nly a p p lie d o n DCH: c a n y o u g ue s s whic h? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 133
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Mapping Logical⇔Transport Channels Control Logical Channels BCCH BCH PCCH PCH CCCH RACH Traffic Logical Channels DCCH FACH DTCH DSCH Common Transport Channels © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CPCH CTCH DCH Dedicated Transport Channels Page 134
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Mapping Logical ⇔ Transport Channels Control Logical Channels BCCH BCH PCCH PCH CCCH RACH Traffic Logical Channels DCCH FACH DTCH DSCH Common Transport Channels © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CPCH CTCH DCH Dedicated Transport Channels Page 135
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Complete the gaps! (1 ) … c ha nne ls are defined by what type of information (e.g user data, signalling, system information...) is transported over the radio interface. (2 ) … c ha nne ls are defined by how and with what characteristics (e.g type of coding, required transfer delay, required BER... ) data are transferred over the radio interface. (3 ) … c ha nne ls are defined by the mechanisms (e.g frequency, code, power, framing...) with which the data are transferred over the physical resources of the airinterface. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 136
  • 5. UTRAN/5.1 From Radio Bearers to transport channels Complete the table! Tra ffic cla ss Sig na lling 1. … 2. … 3. … 4. … - Log ica l Cha nne l Tra nsp ort Ch a nn el BCCH PCCH CCCH DCCH BCH, FACH PCH UL: RACH, DL: FACH RACH, DCH UL: 3 coordinated DCHs DL: 3 coordinated DCHs UL: RACH, DL: FACH UL: CPCH, DCH DL: DSCH,DCH UL: CPCH, DCH DL: DSCH,DCH UL: CPCH, DCH DL: DSCH,DCH FACH Use r inform a tion 5. … Conversational 6. … Interactive 3 DTCHs DTCH 7. … Interactive DTCH 8. … Streaming DTCH 9. … Background DTCH 10. … Background CTCH © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 137
  • 5. UTRAN Layer 3 Layer 2 Layer 1 UE 5.1 From Radio Bearers to transport channels 5.2 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signalling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 RNC Radio Protocols 5.3 Node B Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 138
  • 5. UTRAN/5.2 Radio Protocols Radio protocol stack Non Access Stratum Control plane User plane Be a re rs (c a lle d RA in us e r p la ne ) B Access Stratum control control control Layer 2/ PDCP Layer 2/ BMC control control RRC Layer 3 PDCP PDCP SAP BMC Ra d io Be a re rs Layer 2/ RLC RLC RLC RLC RLC RLC RLC RLC RLC Lo g ic a l Cha nne ls Layer 2/ MAC MAC Tra ns p o rt Cha nne ls Layer 1 PHY Phy s ic a l Cha nne ls © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 139
  • 5. UTRAN/5.2 Radio Protocols Radio Resource Control (RRC) Be a re rs RRC Ra d io Be a re rs (c o ntro l p la ne ) Radio mobility management Measurement control and reporting control control control control control Layer 3 Call management Outer loop power control PDCP BMC RLC MAC PHY RRC is the brain of the radio interface protocol stack. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 140
  • 5. UTRAN/5.2 Radio Protocols PDCP and BMC protocols PDCP (Packet Data Convergence Protocol) - in the user plane, only for services from the PS domain - it contains compression methods In R99 only a header compression method is mentioned (RFC2507). Why is header compression valuable? e.g a combined RTP/UDP/IP headers is at least 60 bytes for IPv6, when IP voice service header can be about 20 bytes or less. BMC (Broadcast/ Multicast Services) - in the user plane - to adapt broadcast and multicast services from NAS on the radio interface In R99 the only service using this protocol is SMS Cell Broadcast Service (directly taken from GSM). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 141
  • 5. UTRAN/5.2 Radio Protocols Radio Link Control (RLC) Segmentation Ra d io Be a re rs (us e r p la ne ) Ra d io Be a re rs (c o ntro l p la ne ) Layer 2/ upper part RLC RLC RLC RLC Co ntro l Lo g ic a l Cha nne ls RLC RLC RLC RLC Tra ffic Lo g ic a l Cha nne ls Buffering Data transfer with 3 configuration modes: - Transparent (TM) - Unacknowledged (UM) - Acknowledged (AM) Ciphering RLC provides segmentation and (in AM mode) reliable data transfer. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 142
  • 5. UTRAN/5.2 Radio Protocols Medium Access Control (MAC) Tra ffic Lo g ic a l Cha nne ls Co ntro l Lo g ic a l Cha nne ls Layer 2/ lower part Basic data transfer Multiplexing of logical channels Priority handling/Scheduling (TFC selection) MAC Tra ns p o rt Cha nne ls (c o m m o n a nd d e d ic a te d ) Reporting of measurements Ciphering MAC can switch a common channel into a dedicated channel if higher bit rate is required (on request of L3-level). MAC can change dynamically Transport Format (bit rate…) of each transport channel on a frame basis (each 10 ms) without interchanging with L3-level. MAC provides flexible data transfer. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 143
  • 5. UTRAN/5.2 Radio Protocols TFC selection in MAC protocol Several transport channels can be time-coordinated to be multiplexed on a CCTrCH before mapping on one physical channel (or more if necessary). Transport Format (TF) e.g. DCH1 = {244} DCH2 = {0 ; 148} DCH3 = {0 ; 148} Transport Format Set (TFS) Transport Format Combination (TFC) MAC TFC selection DCH1 DCH2 DCH3 TrCH multiplexing TFCS = { {244 ; 0 ; 0} , {244 ; 148 ; 0} , {244 ; 0 ; 148} } Transport Format Combination Set (TFCS) MAC selects TFC inside TFCS. There is one TFCS per CCTrCH. >> Why is the combination {244 ; 148 ; 148} not possible? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CCTrCH Physical channel Mapping L1 Physical Channel(s) Page 144
  • 5. UTRAN/5.2 Radio Protocols The Physical Layer Co m m o n Tra ns p o rt Cha nne ls De d ic a te d Tra ns p o rt Cha nne ls Physical layer Layer 1 Co m m o n Phy s ic a l Cha nne ls Air Interface Multiplexing of transport ch. Spreading/modulation RF processing De d ic a te d Phy s ic a l Cha nne ls Power control Measurements The physical layer provides multiplexing and radio frequency processing with a CDMA method. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 145
  • 5. UTRAN/5.2 Radio Protocols Exercise: MAC protocol (1) BCCH PCCH BCCH CCCH CTCH DCCH DTCH DTCH MAC Control MAC-d MAC-b BCH MAC-c/sh PCH FACH FACH RACH CPCH DSCH DSCH DCH DCH Iur or local Look at this figure and answer the questions on the following pages. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 146
  • 5. UTRAN/5.2 Radio Protocols Exercise: MAC protocol (2) 1. On which logical/transport channels will be mapped: - system information broadcasting - paging - telephony speech - internet browsing at a high bit rate - internet browsing at a low bit rate Can you imagine a situation where the UE will use 2 DTCHs (or more) at the same time? 2. Guess the meaning of “MAC-b” “MAC-c/ and “MAC-d”. sh” 3. Why is there one MAC-d entity on the UE side and several MAC-d entities on the UTRAN side? 4. What is the link between MAC-c/sh and MAC-d for? 5. What are the 4 main functions of MAC protocol? 6. MAC can multiplex logical channels only if they require the same QoS: true or false? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 147
  • 5. UTRAN/5.2 Radio Protocols Exercise: MAC protocol (3) 7. RNTI (Radio Network Temporary Identity) is an UE identity assigned by UTRAN, when the UE is connected to the UTRAN . The parameter RNTI is included in the header of each transport blocks in MAC-c/sh, but not in MAC-d : can you explain the reason? 8. The system can also multiplex transport channels: where does that take place? 9. What is the name of the channel on which several time-coordinated transport channels can be multiplexed? 10. Which entity is responsible for TFC selection? TFCS allocation? 11. Is it possible to multiplex 2 FACHs (or more)? 2 DCHs (or more)? a FACH and a DCH? 12. Will the physical channel configuration be changed (e.g modification of spreading factor) when MAC selects a new TFC inside TFCS? 13. MAC makes measurement reports to RRC: why is it necessary? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 148
  • 5. UTRAN Layer 3 Layer 2 Layer 1 UE 5.1 From Radio Bearers to transport channels 5.2 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signaling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 RNC Radio Protocols 5.3 Node B Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 149
  • 5. UTRAN/ 5.3 Iu protocols General model The same general protocol model is applied for all Iu interfaces: Radio Network Layer Transport Control Plane Application Protocol Transport Network User Plane Data Stream(s) Transport Network Control Plane Transport Network User Plane ALCAP Network Layer User Plane Signaling Bearer(s) Signaling Bearer(s) Physical Layer Application Protocols: © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Data Bearer(s) 1. What is the purpose of the separation between the Radio Network Layer and the Transport Network Layer? 2. Why is ALCAP protocol necessary? - NBAP for Iub interface - RNSAP for Iur interface - RANAP for Iu-CS and Iu-PS interfaces Page 150
  • 5. UTRAN/ 5.3 Iu protocols Iub protocols Ra d io Link Es ta blis hm e nt RNC Radio Network Layer Transport RA * Bs RRC Co nne c tio n Es ta blis hm e nt* N S s ig na lling * A Control Plane User Plane NBAP Frame Protocols (IubFP) Transport Network User Plane Transport Network Control Plane ALCAP Network Layer Transport Network User Plane AAL5 AAL5 AAL2 ATM Physical Layer * a t this s ta g e the s e d a ta s tre a m s ha v e be e n m a p p e d o n tra ns p o rt c ha nne ls by M C p ro to c o l A © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Node B Page 151
  • 5. UTRAN/ 5.3 Iu protocols Iur protocols SRNC Es ta blis hm e nt o f a n a d d itio na l ra d io link to a n UE (fo r s o ft HO ) Radio Network Layer Transport RA * Bs RRC Co nne c tio n Es ta blis hm e nt* N S s ig na lling * A Control Plane User Plane RNSAP Frame Protocols (Iur FP) Transport Network User Plane Network Transport Network User Plane ALCAP ... Layer Transport Network Control Plane AAL5 AAL5 AAL2 ATM Physical Layer * a t this s ta g e the s e d a ta s tre a m s ha v e be e n m a p p e d o n tra ns p o rt c ha nne ls by M C p ro to c o l A © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U DRNC Page 152
  • 5. UTRAN/ 5.3 Iu protocols UTRAN protocols: general recap RRC PDCPBMC RLC MAC RRC PDCPBMC Uu RLC Iub SRNC Softer combining UE Phy. (air) Soft combining ... ... AAL5 AAL5 AAL2 NBAP ALCAP Iub-FP Iur-FP ALCAPRNSAP ... ... ... ... AAL5 AAL5 AAL2 AAL2 AAL5 AAL5 ATM/Physical layer Soft(er) combining Phy. (air) MAC ATM/Physical layer NBAP ALCAP Iub-FP Node-B Iur RRC PDCPBMC Radio Protocols Iu Protocols (Radio Network Layer) Iu protocols (Transport Network Layer) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U RLC DRNC MAC NBAP ALCAP Iub-FP Iur-FP ALCAPRNSAP ... ... ... ... AAL5 AAL5 AAL2 AAL2 AAL5 AAL5 ATM/Physical layer Page 153
  • 5. UTRAN 5.1 From Radio Bearers to transport channels 5.2 Radio Protocols 5.3 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signalling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 ? Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U ? Page 154
  • 5. UTRAN/5.4 UE identifiers and UE states UE identifiers 2 types of UE identification on the radio interface: • NAS identifiers - IMSI: International Mobile Subscriber Identity - TMSI: Temporary Mobile Station Identity They are used in the initial access CCCH message • UTRAN identifier - RNTI: Radio Network Temporary Identity This is allocated by the UTRAN for each UE in connected mode and used for inband identification in common transport channels (e.g FACH). The RNTI is not used outside the UTRAN. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 155
  • 5. UTRAN/5.4 UE identifiers and UE states UE states (1) RRC Connection Release out of coverage UE UE UE detached in idle mode in connected mode “just after switch on” process Including Ce ll s e a rc h p ro c e d ure RRC Connection Establishment Why is the idle mode necessary? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 156
  • 5. UTRAN/5.4 UE identifiers and UE states UE states (2) RRC Connection Release out of coverage R C Connection E R stablishm procedure ent UE UE UE in connected detached in idle mode mode “just after switch on” process CCCH RNC 1 RRC Connection Establishment - UE in idle mode, - a Common Control Channel (CCCH) is used to initiate the procedure CCCH DCCH DCCH RNC RNC 2 - Setup of a Dedicated Control Channel (DCCH) 3 - UE in connected mode - The DCCH is used during the whole time of the RRC connection to carry signalling dedicated to this particular UE Which type of transport channel are used to carry CCCH? DCCH? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 157
  • 5. UTRAN/5.4 UE identifiers and UE states UE states (3) Cell_DCH state Signalling and traffic data dedicated to the UE (mapped on DCCH and DTCH respectively) are carried on DCH transport channel UE UEin connected Cell DCH m ode Cell PCH in id le m o de Cell FACH URA PCH Cell_FACH state Signalling and traffic data dedicated to the UE (mapped on DCCH and DTCH respectively) are carried on RACH (uplink) and FACH (downlink) transport channels © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Cell_DCH ⇒Cell_FACH No traffic UL/ at expiry of timer 1 DL Cell_FACH ⇒Cell_DCH Traffic volume UL/ too large DL Page 158
  • 5. UTRAN/5.4 UE identifiers and UE states UE states (4) Cell_PCH state No transmission of signalling and traffic data dedicated to the UE (no DCCH and no DTCH) But the RRC connection is still active (UTRAN keeps RNTI for UE) and UE location at a cell level. UE URA_PCH state Very similar to cell_PCH state UTRAN keeps the location of the UE at the URA level (set of UMTS cells) m o de UEin connected m ode Cell PCH in id le - a DCCH (and possibly a DTCH) can be reestablished very quickly (this procedure is initiated by sending a paging signal PCH) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Cell DCH Cell FACH URA PCH Cell_FACH ⇒Cell_PCH No traffic UL/ at expiry of timer 2 DL Cell_PCH ⇒ Cell_FACH ⇒URA_PCH Too many cell reselections Cell/ URA_PCH ⇒ Cell_FACH Incoming DL or UL traffic Page 159
  • 5. UTRAN/5.4 UE identifiers and UE states UE identifiers and UE states: complete the table! UE Sta te s CN UTRAN UE Id e ntifie rs UE Loca tion UE Id e ntifie r UE Loca tion id le m od e IMSI, TMSI LA, RA ce ll_DCH conn e cte d m ode ce ll_FACH ce ll_PCH URA_PCH © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 160
  • 5. UTRAN Layer 3 Layer 2 Layer 1 UE 5.1 Radio Protocols 5.3 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signaling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 RNC From Radio Bearers to transport channels 5.2 Node B Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 161
  • 5. UTRAN/5.5 Signaling procedures List of basic signaling procedures A. Broadcast of system information B. Paging B1. Paging Type 1 (in idle mode or in cell_PCH or in URA_PCH states) B2. Paging Type 2 (in cell_FACH or cell_DCH states) C. RRC Connection C1. RRC Connection Establishment (to cell_FACH and to cell_DCH states) C2. RRC Connection Release (in cell_DCH states) D. Radio Link establishment E. Direct Transfer F. Control of RAB, RB, Transport Channel and Physical Channel F1. RAB Establishment F2. Physical Channel Reconfiguration G. Soft HO (Radio Link Addition) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 162
  • 5. UTRAN/5.5 Signaling procedures How to read call scenario diagrams Name of the message Logical channel Transport channel RNC UE RRC 1. RRC Co nne c tio n Re q ue s t (CCCH:RACH) Initial UE identity, Establishment cause, Initial UE capability RRC Network entity Protocol entity Parameters of the message © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 163
  • 5. UTRAN/5.5 Signaling procedures A. System Information Broadcasting (1) The broadcast system information: - may come from CN, RNC or Node-B. - contains static parameters (Cell identity, supported PLMN types...) and dynamic parameters (UL interference level...). - is arranged in System Information Blocks (SIB), which group together elements of the same nature. - can be carried on BCH which is transmitted permanently over the entire cell. >> Do you think the UE needs to read all the SIBs each time a broadcast is repeated? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 164
  • 5. UTRAN/5.5 Signaling procedures A. System Information Broadcasting (2) UE RNC Node-B NBAP NBAP RRC Sy s te m I rm a tio n (BCCH:BCH) nfo RRC Master/Segment Info Block(s) Sy s te m I rm a tio n nfo Up d a te Re q ue s t NBAP Master/Segment Info Block(s), BCCH modification time Sy s te m I rm a tio n nfo Up d a te Re s p o ns e NBAP Sy s te m I rm a tio n (BCCH:BCH) nfo RRC Master/Segment Info Block(s) RRC CN RRC Sy s te m I rm a tio n (BCCH:BCH) nfo RRC Master/Segment Info Block(s) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U >> Why does RRC protocol terminate at Node-B for BCH (not at RNC)? Page 165
  • 5. UTRAN/5.5 Signaling procedures B. Paging Paging is typically used at core network-originated call. UE in idle mode The network will page the UE in LA (CS domain) or RA (PS domain) UE is in connected mode The network will page the UE: - in the cell (in cell_PCH, cell_FACH, cell_DCH states) - in the URA (in URA_PCH state) Pa g ing Ty p e 1 : mapped on PCCH/PCH Pa g ing Ty p e 2 : mapped on DCCH/FACH or DCCH/DCH >> Can you guess which Paging Type will be use in idle mode? in cell_PCH state? in cell_FACH state? in cell_DCH state? in URA_PCH state? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 166
  • 5. UTRAN/5.5 Signaling procedures B1. Paging Type 1 UE 1 UE 2 Node-B 1 Node-B 2 R 1 NC RANAP 1 . Pa g ing CN Domain Indicator, UE identity, Paging cause RANAP RRC 2 . Pa g ing Ty p e 1 (PCCH:PCH) RRC 1 . Pa g ing Idem RANAP RANAP RRC 2 . Pa g ing Ty p e 1 (PCCH:PCH) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CN RNC 2 RRC Page 167
  • 5. UTRAN/5.5 Signaling procedures B2. Paging Type 2 UE Node-B RANAP RRC 2 . Pa g ing Ty p e 2 (DCCH:FACH or DCH) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CN SRNC 1 . Pa g ing CN Domain Indicator, UE identity, Paging cause RANAP RRC Page 168
  • 5. UTRAN/5.5 Signaling procedures C. RRC connection RRC connection is established at the initial access (after cell search procedure when the UE is camping on a cell). After RRC connection establishment: - UE will switch from idle mode to cell_FACH or cell_DCH states. - UE will have a signalling link with UTRAN (on DCCH) UE needs to establish a RRC connection prior to making : - voice call - location update - measurement reporting ... © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 169
  • 5. UTRAN/5.5 Signaling procedures C1. RRC Connection Establishment UE RRC Node-B 1. RRC Co nne c tio n Re q ue s t (CCCH:RACH) Initial UE identity, Establishment cause, Initial UE capability RNC RRC 2. Allocate RNTI, Select Level 1 and Level 2 parameters (e.g. TFCS, scrambling code) 3. Radio Link Establishment (see Pro c e d ure D) RRC RRC 4. RRC Co nne c tio n Se tup (CCCH:FACH) Initial UE identity, RNTI, capability update requirement, TFS, TFCS, frequency, UL scrambling code, power control info 5. RRC Co nne c tio n Se tup Co m p le te (DCCH:RACH or DCH) Integrity information, ciphering information RRC RRC >> Can the UE send user information (e.g voice call) after completing this stage? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 170
  • 5. UTRAN/5.5 Signaling procedures C2. RRC Connection Release (in cell_DCH state) UE Node-B of DRNC DRNC Node-B of SRNC CN SRNC RANAP 1 . I Re le a s e u Co m m a nd Cause RANAP 2 . I Re le a s e u Co m p le te RANAP RANAP - 3. ALCAP Iu Bearer Release RRC RRC 4. RRC Co nne c tio n Re le a s e (DCCH:DCH ) Cause 5. RRC Co nne c tio n Re le a s e Co m p le te (DCCH:DCH ) - RRC RRC 6. Radio Link Deletion 7. Radio Link Deletion 8. Radio Link Deletion © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 171
  • 5. UTRAN/5.5 Signaling procedures D. Radio Link (RL) Establishment for a DCH RNC Node-B NBAP Start RX Ra d io Link Se tup Re q ue s t Cell id, TFS, TFCS, frequency, UL scrambling code, power control info NBAP ALCAP Iub Data Transport Bearer Setup Ra d io Link Se tup Re s p o ns e NBAP Iub-FP Do wnlink s y nc hro nis a tio n Iub-FP Iub-FP Up link s y nc hro nis a tio n Iub-FP NBAP Signalling link termination, transport layer addressing info Start TX >> Are NBAP, ALCAP and RRC messages carried on the same transport bearers on Iub? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 172
  • 5. UTRAN/5.5 Signaling procedures E. Direct Transfer The mechanism to transfer signalling from higher layers (NAS signaling) through messages of RRC protocol is called Dire c t Tra ns fe r. UE Node-B RANAP RRC RRC 2 . Do wnlink Dire c t Tra ns fe r (DCCH:FACH or DCH) NAS message 1 ’. Up link Dire c t Tra ns fe r (DCCH:RACH or DCH) CN node indicator, NAS message 1. Dire c t Tra ns fe r CN Domain Indicator, NAS PDU RANAP RRC >> Can you mention some examples of use of Dire c t Tra ns fe r? RRC RANAP © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CN SRNC 2’. Dire c t Tra ns fe r CN Domain Indicator, NAS PDU RANAP Page 173
  • 5. UTRAN/5.5 Signaling procedures F. Control of RAB, RB, Transport and Physical Channels These procedures take place after RRC connection establishment: the UE is either on cell_FACH or cell_DCH state. A RAB is mapped on one or more RB(s). A RB establishment consists of: - performing admission control (see RRM: Radio Resource Management) - setting parameters describing RB processing in layer 2 (e.g TFS, TFCS) and in layer 1 (codes, power control) RAB and RB can be reconfigured during an active connection. The transport channels and physical channels parameters are included in the RB but can also be reconfigured separately with transport and physical channel dedicated procedures (Tra ns p o rt Cha nne l Re c o nfig ura tio n and Phy s ic a l Cha nne l Re c o nfig ura tio n). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 174
  • 5. UTRAN/5.5 Signaling procedures F1. RAB Establishment UE RNC Node-B RANAP 1. RA A s ig nm e nt B s Re q ue s t RAB parameters, User plane mode, Transport Address, Iu Transport association CN RANAP 2. ALCAP Iu Data Transport Bearer Setup 3. Radio Link Establishment (see Pro c e d ure D) RRC 4. RB Se tup (DCCH:FACH or DCH ) TFS, TFCS... RRC 5. RB Se tup Co m p le te (DCCH:RACH or DCH ) RRC RRC - RANAP 6. RA A s ig nm e nt B s Re s p o ns e - RANAP >> Can the UE send user information (e.g voice call) after completing this stage? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 175
  • 5. UTRAN/5.5 Signaling procedures F2. Physical Channel Reconfiguration UE Node-B of DRNC DR NC 1. RL Re c o nfig . Pre p a re NBAP NBAP DL scrambling code 2. RL Re c o nfig . Re a d y NBAP NBAP - RNSAP RNSAP NBAP RRC RRC 5. RL Re c o nfig . Co m m it SRNC 3. DL scrambling code 4. RNSAP NBAP 6. Phy s ic a l Cha nne l Re c o nfig ura tio n (DCCH:DCH ) DL scrambling code 7. Phy s ic a l Cha nne l Re c o nfig ura tio n Co m p le te (DCCH:DCH ) - RNSAP RRC RRC >> What is the difference between NBAP and RNSAP? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 176
  • 5. UTRAN/5.5 Signaling procedures G. Soft HO (Radio Link Addition) UE Node-B of DRNC DR NC SRNC 1. Decision to setup new RL RNSAP 2 . RL Se tup Re q ue s t - RNSAP 3. Radio Link Establishment (see Pro c e d ure D) 4. ALCAP Iur Data Transport Bearer Setup RNSAP RRC RRC 5 . RL Se tup Re s p o ns e 6. A tiv e Se t Up d a te (DCCH:DCH ) c - 7. A tive Se t Up d a te Co m p le te (DCCH:DCH ) c © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U - - RNSAP RRC RRC Page 177
  • 5. UTRAN/5.5 Signaling procedures EXERCICE Please complete the procedure diagrams on the following slides by using the elementary procedure previously described Duration : 10 minutes © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 178
  • 5. UTRAN/5.5 Signalling procedures Location Update Find the missing procedure names! UE UE d e ta c he d RNC Node-B CN 0. “Just after switch on” process UE in id le m o d e 1. ... UE in c o nne c te d m o d e MM: Lo c a tio n Up d a ting Re q ue s t 2. ... MM: A uthe ntic a tio n Re q ue s t MM: A uthe ntic a tio n Re s p o ns e 3. Security procedures 4. ... MM: Lo c a tio n Up d a ting A c e p t c 5. ... UE in id le m o d e © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 179
  • 5. UTRAN/5.5 Signalling procedures Mobile terminated call Find the missing procedure names! UE RNC Node-B CN 0. “Just after switch on” process 1. ... 2. ... RR: Pa g ing Re s p o ns e 3. ... MM: A uthe ntic a tio n Re q ue s t MM: A uthe ntic a tio n Re s p o ns e 4. Security procedures 5. ... CC: Ca ll Co nfirm CC: A rting le CC: Co nne c t © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CC: Se tup 6. ... 7. ... CC: Co nne c t A kno wle d g e c Page 180
  • 5. UTRAN Layer 3 Layer 2 Layer 1 5.1 UE From Radio Bearers to transport channels 5.2 Radio Protocols 5.3 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signalling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource management (RRM) 5.8 Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Node B RNC Page 181
  • 5. UTRAN/5.6 The Physical Layer Physical Layer Process Transport Channels Channel Coding Convolutional coding, Turbo coding Radio Frame Segmentation 10 ms frame duration 15 time slots Transport Channel Multiplexing Physical Channel Mapping CCtrCH DPDCH, DPCCH, PRACH... Spreading Layer 1 Channelization codes Scrambling codes Modulation QPSK Physical Channels spread over 5 MHz bandwidth © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 182
  • 5. UTRAN/5.6 The Physical Layer Radio Frame Structure … 1 Radio Frame : = 15 Time Slots 10ms …. 1 Time slot : = N bits (according to the bit rate after channel coding) 0.6666 ms 1 Bit : .. = M chips (M is equal to the spreading factor) The bit rate may be changed for each frame (10 ms). Fast power control may be performed for each time slot (0,666 ms). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 183
  • 5. UTRAN/5.6 The Physical Layer Transport Channel Multiplexing DCH 1 DCH 2 Channel Coding Channel Coding Transport Channel Multiplexing CCTrCH Physical Channel Mapping One Physical Channel (or more if necessary) Two transport channels can be mapped onto the same physical channel (for one user). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 184
  • 5. UTRAN/5.6 The Physical Layer Physical channels Phy s ic a l c ha nne ls are defined by the mechanisms (e.g frequency, code, power, framing...) with which the data are transferred over the physical resources of the air-interface. • Physical channels are defined mainly by: - a specific carrier frequency - a scrambling code - a channelization code - start & stop instants (giving a time duration, measured in integer multiples of chips) • Physical channels are sent continuously on the air interface between start and stop instants. • Physical channels are separated by means of quasi-orthogonal codes (2 physical channels shall not have the same channelization code / scrambling code combination). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 185
  • 5. UTRAN/5.6 The Physical Layer Uplink Physical Channels Common Channels Physical Random Access Channel (PRACH) Physical Common Packet Channel (PCPCH) Node B Associated with Transport Channels Dedicated Channels Dedicated Physical Data Channel (DPDCH) Associated with Transport Channels Dedicated Physical Control Channel (DPCCH) NOT associated with Transport Channels © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 186
  • 5. UTRAN/5.6 The Physical Layer e.g. Uplink DPDCH/ DPCCH Data DPDCH DPCCH Ndata bits Pilot TFCI Npilot bits NTFCI bits FBI NFBI bits TPC NTPC bits Tslot = 2560 chips, 10*2k bits (k=0..6) 1 Radio Frame Slot #0 Slot #1 Slot #i Slot #14 T = 10 ms DPDCH carries the dedicated data generated at layer 2 (ie the Dedicated Transport Channel DCH). f DPCCH carries the dedicated signalling of the physical layer, which is required to convey DPDCH. DPCCH is not visible above the physical layer, it is not carried by any transport channels. Under long scrambling code. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 187
  • 5. UTRAN/5.6 The Physical Layer e.g. Uplink PRACH When attempting to access the network, the mobile has no dedicated code yet and must choose randomly a code in a set of codes. Collisions may occur between two mobiles. radio frame: 10 ms radio frame: 10 ms 5120 chips #0 Access slot #0 Access slot #1 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 Random Access Transmission Random Access Transmission Access slot #7 Access slot #8 Random Access Transmission A mobile can only begin to transmit at a certain access slot (slotted ALOHA). 15 access slots have been defined (nothing to do with the time slots of the radio frame!). Random Access Transmission Access slot #14 The PRACH has a Random Access Transmission to limit risk of collision. It is based on a Slotted ALOHA approach with fast acquisition indication. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 188
  • 5. UTRAN/5.6 The Physical Layer Downlink Physical Channels Common Channels Primary Common Control Physical Channel (P-CCPCH) Secondary Common Control Physical Channel (S-CCPCH) Physical Downlink Shared Channel (PDSCH) Associated with Transport Channels Synchronisation Channel (SCH) Node B Common Pilot Channel (CPICH) Page Indicator Channel (PICH) NOT associated with Transport Channels Acquisition Indication Channel (AICH) Dedicated Channels Dedicated Physical Data Channel (DPDCH) Dedicated Physical Control Channel (DPCCH) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Associated with Transport Channels NOT associated with Transport Channels Page 189
  • 5. UTRAN/5.6 The Physical Layer e.g. Downlink DPDCH/ DPCCH DPCCH DPDCH Data1 N data1 bits TPC N TPC bits DPDCH TFCI N TFCI bits DPCCH Data2 Pilot N data2 bits N pilot bits Tslot= 2560 chips, 10*2k bits (k=0..7) Slot #0 Slot #1 Slot #i Slot #14 One radio frame, Tf = 10 ms Similar to uplink, but DPDCH and DPCCH are time-multiplexed. The SF may range from 256 to 8. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 190
  • 5. UTRAN/5.6 The Physical Layer e.g. Downlink PCCPCH 256 chips Data 18 bits ( Tx OFF) Tslot = 2560 chips , 20 bits Slot #0 Slot #1 Slot #i Slot #14 1 radio frame: Tf = 10 ms The Primary CCPCH carries the BCH, which provides system- and cellspecific information (e.g set of uplink scrambling codes) The P-CCPCH is a fixed rate (30 kbps, SF=256) DL physical channel, which provide a timing reference for all physical channels (directly for DL, indirectly for UL). CCPCH is scrambled under the Primary Scrambling code. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 191
  • 5. UTRAN/5.6 The Physical Layer e.g. CPICH (pilot) Pre-defined symbol sequence Tslot = 2560 chips , 20 bits = 10 symbols Slot #0 Slot #1 Slot #i Slot #14 1 radio frame: Tf = 10 ms CPICH (or Pilot or Beacon) The pilot carries a pre-defined symbol sequence at a fixed rate (SF=256). It is a re fe re nc e : - to aid the channel estimation at the terminal (time or phase reference) - to perform handover measurements and cell selection/reselection (power reference) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 192
  • 5. UTRAN/5.6 The Physical Layer e.g SCH and the cell search procedure Slot #0 Primary SCH Secondary SCH acp acs i,0 Slot #1 acp acs Slot #14 acp i,1 acs i,14 256 chips 2560 chips One 10 ms SCH radio frame SCH (Synchronisation Channel) It can be detected by the UE just after switch on, as the SCH consist of a 256 modulated code sequence which is the same for every cell in the system. It is used by the UE in the cell search procedure to get the (downlink) scrambling code of the cell. After c e ll s e a rc h p ro c e d ure , the terminal can read system and cell- specific BCH information. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 193
  • 5. UTRAN/5.6 The Physical Layer Mapping Transport⇔Physical Channels P-CCPCH PCH Primary Common Control Physical Channel S-CCPH BCH Secondary Common Control Physical Channel FACH PRACH DCH Physical Downlink Shared Channel DPDCH DSCH Physical Common Packet Channel PDSCH CPCH Physical Random Access Channel PCPCH RACH Dedicated Physical Data Channel Physical channels not mapped on transport channels: DPCCH SCH CPICH PICH AICH Dedicated Physical Control Channel (uplink and downlink) Synchronisation Channel Common Pilot Channel Page Indicator Channel Acquisition Indication Channel © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 194
  • 5. UTRAN/5.6 The Physical Layer Example 1: UL 64 kbps data (1) In this example, a RB (Radio Bearer) is mapped (in RLC) on DTCH which is mapped (in MAC) on DCH. The DCH has the TFS (Transport Format Set): Transport block size Transport block set size CRC Coding TTI 640 bits 4*640 bits 16 bits Turbo coding, coding rate = 1/3 40 ms #4 640 640 640 640 #3 640 640 640 640 #2 640 640 640 640 #1 640 640 640 640 40 ms This example can be applied for ISDN service. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 195
  • 5. UTRAN/5.6 The Physical Layer Example 1: UL 64 kbps data (2) Transport block CRC attachment #1 640 #1 640 CRC CRC 16 2624 Turbo coding R=1/3 7872 Tail bit attachment Tail 7872 1st interleaving Rate matching #4 640 16 TrBk concatenation Radio frame segmentation #4 640 12 7884 #1 1971 #4 1971 #1 1971+N #4 RM1 1971+N What is the radio frame length? Can you deduce the spreading factor (SF)? RM4 To TrCh Multiplexing (see further) Extracted from 3GPP 25.944 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 196
  • 5. UTRAN/5.6 The Physical Layer Example 2: UL 3,4 kbps data (1) In this example, a SRB (Signalling Radio Bearer) is mapped (in RLC) on DCCH which is mapped (in MAC) on DCH. The DCH has the TFS (Transport Format Set): Transport block size Transport block set size CRC Coding TTI 148 148 148 bits 0, 148 bits 16 bits CC, coding rate = 1/3 40 ms 148 40 ms >> Assuming that RLC and MAC overhead in a transport block is 12 bits, can you determine the bit rate of this SRB? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 197
  • 5. UTRAN/5.6 The Physical Layer Example 2: UL 3,4 kbps data (2) Transport block 148 CRC attachment 148 TrBks (B =0,1) TrBks concatenation What is the radio frame length? Can you deduce the spreading factor? 516*B #1 129*B #1 129*B +NRM1 © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U 8*B 516*B 1st interleaving Extracted from 3GPP 25.944 Tail 164*B Convolutional Coding, CR = 1/3 Rate matching 16 164 Tail bit attachment Radio frame Segmentation CRC #2 129*B #2 #3 129*B 129*B +NRM2 #4 129*B #3 #4 129*B +NRM3 129*B +NRM4 To TrCh Multiplexing (see further) Page 198
  • 5. UTRAN/5.6 The Physical Layer UL TrCH multiplexing of 64 kbps and 3,4 kbps data UL 64 kbps data TrCH multiplexing #1 #2 #1 #1 #3 #2 UL 3,4 kbps data #4 #2 #1 #3 #3 #2 #3 #4 #4 #4 2nd interleaving Physical channel mapping ?? kbps DPDCH CFN=4N 15 kbps DPCCH CFN=4N+1 CFN=4N+2 CFN=4N+3 CFN=4N CFN=4N+1 CFN=4N+2 CFN=4N+3 >> On which physical channel are the UL 64 kbps data and the UL 3,4 kbps data? what is the spreading factor mapped? what is the DPDCH bit rate? >> What is carried on DPCCH ? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 199
  • 5. UTRAN 5.1 From Radio Bearers to transport channels 5.2 Radio Protocols 5.3 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signalling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 no Mobility Management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U yes Page 200
  • 5. UTRAN/5.7 Radio Resource Management (RRM) RRM purposes RRM is a set of algorithms to manage radio resources: • Maximise the amount of radio resources available Power control algorithms Handover algorithms • Allocation of radio resources Which type of transport channel, transport format should be chosen to meet QoS requirements? • Admission Control In which conditions can a new user be admitted? • Load Control (congestion control) What should be done to avoid congestion? In RRM all layers are involved under RRC control. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 201
  • 5. UTRAN/5.7 Radio Resource Management (RRM) RRM functions UE dedicated functions, implemented in SRNC and Node B: Selection of radio bearer parameters according to RAB requirements Closed loop power control Handover control RRC states management according to UE traffic volume DL dynamic scheduling on DCH UTRAN dedicated functions, implemented in CRNC: Radio admission control Code allocation Radio load control Open loop power control © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 202
  • 5. UTRAN/5.7 Radio Resource Management (RRM) Transport channel allocation strategies UL / DL RACH /FACH Co m m o n c ha nne ls low setup time, but continuous transmission not maintained no soft HO and no fast PC Sha re d c ha nne ls CPCH /DSCH no guarantee of delay no soft HO, but fast PC DCH /DCH De d ic a te d c ha nne ls bit rate can be changed during transmission (TFS) soft HO and fast PC © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Short packets Bursty traffic to be sent immediately Medium packets Bursty and delayinsensitive traffic Long packets Constant and variable bit rate traffic with low delay requirement (LCD) High bit rate Page 203
  • 5. UTRAN/5.7 Radio Resource Management (RRM) Admission and Load Control Both procedures are handled by CRNC. They are estimated separately for uplink and downlink directions. Admission Control This algorithm is executed when a radio bearer is to be setup or modified. It is based on: •Power transmission criteria (noise increase in UL, transmit capacity in DL) •Number of active users in the frequency band (code management) And performed according to: •The type of required QoS •The current system load Load Control (Congestion Control) This algorithm ensures that the system is not overloaded and remains stable. In case of congestion some actions can be taken. But overload situations should normally be exceptional. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 204
  • 5. UTRAN Layer 3 Layer 2 Layer 1 UE 5.1 Radio Protocols 5.3 Iu Protocols 5.4 UE identifiers and UE states 5.5 Signalling procedures 5.6 The Physical Layer (on the air interface) 5.7 Radio Resource Management (RRM) 5.8 RNC From Radio Bearers to transport channels 5.2 Node B Mobility management © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 205
  • 5. UTRAN/5.8 Mobility management General description (1/ 2) The mobility management enables a user to have access to the subscribed services on the whole coverage of the usual network and possibly visited networks. It is performed as long as the UE remains switched on. It needs a lot of radio and network resources. • UE in idle mode (network mobility) Wherever the UE is located in the network coverage: - the UE should have an access point to the network in the uplink >> Cell reselection mechanisms - the network should be able to reach the UE in the downlink (paging) >> Location Area (LA) / Routing Area (RA) update mechanisms • UE in connected mode (radio mobility management) A connection to the UTRAN (RRC connection) has been established: this connection should remain, when the UE moves from one cell to another. >> Handover (HO) or cell update mechanisms © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 206
  • 5. UTRAN/5.8 Mobility management General description (2/ 2) • UE in idle mode This mode is entered after “just after switch on” process. The UE location is: - known by the CN at LA or RA level - not known by the UTRAN • UE in connected mode UE UTRAN Detached “Just after switch on” process Idle mode RRC connection establishment This mode is entered after RRC connection establishment. The UE location is: Connected mode - known by the CN at a LA or RA level (furthermore the MSC or the SGSN Uu knows the SRNC of the UE) - known by the UTRAN at a cell or URA level. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 207
  • 5. UTRAN/5.8 Mobility management UE in idle mode (1/ 2) When moving across the network, the UE may have to perform a cell reselection, if the initial cell on which it is camped is no longer available or is no longer the best suited. ? The cell reselection consists of a selection of candidate cells and a ranking of these cells according to radio criteria. The cell reselection is performed autonomously by the UE, but the network can influence it by changing the radio parameters used in radio criteria. These radio parameters are transmitted in the Broadcast Channel (BCH). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 208
  • 5. UTRAN/5.8 Mobility management UE in idle mode (2/ 2) VLR Location Area (LA) VLR ... ... HLR SGSN SGSN Routing Area (RA) When camping on a cell, the terminal must register its LA and/or its RA. When the terminal moves across the network, it must update its LA (RA) which is stored in VLR (SGSN) in the Core Network. LA (RA) Update is performed periodically or when entering a new LA (RA). © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 209
  • 5. UTRAN/5.8 Mobility management UE in connected mode (1/ 3) MM mechanisms Effect during the call hard HO soft HO hard HO cell update very short cut no cut very short cut suspended C ell_PC H cell update suspended URA_PC H URA update suspended C ell_DC H C ell_FAC H Cell update (URA update) consists of updating the MS location information stored in the SRNC. A UTRA originated paging message will therefore be sent only in this cell (this URA) and not in a whole LA or RA. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 210
  • 5. UTRAN/5.8 Mobility management UE in connected mode (2/ 3) Soft HO •inter-cell (softer HO, managed by Node-B) •inter Node-B •inter-RNC (SRNS relocation) Hard HO cell 1 cell 2 •intra CDMA-carrier not recommended for dedicated channels, but necessary for common channels for which soft HO is not applied •inter CDMA-carrier one operator can have two CDMA carriers or more between two different operators •inter-mode FDD-TDD (not provided in R99) •inter-system UMTS-GSM: necessary to provide continuous coverage UMTS-CDMA2000 (in the US?) Cell reselection •Inter-system : UMTS/GPRS (inter/intra carrier, inter/intra RNC) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 211
  • 5. UTRAN/5.8 Mobility management UE in connected mode (3/ 3) A hard handover consists of forwarding a call on another channel which is running on a different carrier. The terminal must make measurements on other frequencies (FFD, GSM or TDD frequencies) whilst holding the on-going connection : - Dual receiver •simple handover operation, but expensive receiver UTRA cell GSM cell - Compressed mode (or slotted mode) •simple receiver, but complicated handover operation •the information is compressed time periodically (a few ms), in order to perform measurements on the other frequencies without losing data Downlink 10ms frame Compressed frame © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Idle period Page 212
  • 5. UTRAN/5.8 Mobility management Exercise 1. The c e ll re s e le c tio n is easier than the initia l c e ll s e le c tio n (performed just after switch on): can you find the reason? 2. What is the difference between the c e ll re s e le c tio n and the c e ll up d a te (performed in cell_PCH state)? 3. If there were no LA/RA update mechanisms, what would happen? 4. Is it better to have small or large LA? 5. Why is soft HO not provided in cell_FACH state? 6. In which case is it be better for the network to move a UE to URA_PCH state rather than to cell_PCH state? © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 213
  • Appendix • “Just after switch on” process • AMR codec •NBAP elementary procedures •RANAP elementary procedures © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 214
  • Appendix/”Just after switch on” process PLMN selection PLMN selection Lis t o f a va ila ble PLM s N UE s witc he d on 1 1 After switch on, the UE: - scans the entire frequency bandwidths of UTRAN FDD and GSM (c e ll s e a rc h p ro c e d ure for UTRAN FDD ) Se le c te d 2 PLM N - monitors the broadcast channels (BCCH for UTRAN FDD) to get the PLMN identifiers. Cell selection Attachment Hence the UE can establish a list of PLMNs which are available in its location. 2 In the list of available PLMNs, the UE selects: - the HPLMN (Home PLMN) if it is available - otherwise another PLMN (national or international) according to priority rules possibly stored in the USIM © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 215
  • Appendix/”Just after switch on” process Attachment procedure PLMN selection 3 In the selected PLMN, the UE: - selects the best cell according to radio criteria - initiates attachment procedure on the selected cell 4 5 Cell selection A c htta m e nt 3 re q ue s t A c htta 4 m e nt re s ult - authentication procedure - storage of subscriber data from the HLR in the VLR (or in the SGSN for PS domain) - allocation of the TMSI (P-TMSI for PS domain) Attachment 5 I ic a tio n o f s e rvic e nd to the UE © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U During the attachment procedure (called I S Ia tta c h M for CS domain, G PRS a tta c h for PS domain), the UE indicates its presence to the PLMN for the purpose of using services: The result of the procedure is notified to the UE: - if successful, the UE can access services - if it fails, the UE can only perform emergency calls Page 216
  • Appendix/AMR codec AMR codec (for CS domain) AMR m od e Source cod in g b it- ra te AMR _12.20 AMR _10.20 AMR _7.95 AMR _7.40 AMR _6.70 AMR _5.90 AMR _5.15 AMR _4.75 12.20 kbit/ s (GSM EFR ) 10.20 kbit/ s 7.95 kbit/ s 7.40 kbit/ s (IS-641) 6.70 kbit/ s (PDC-E ) FR 5.90 kbit/ s 5.15 kbit/ s 4.75 kbit/ s Cla ss A Cla ss B Cla ss C 81 65 75 61 58 55 49 42 103 99 84 87 76 63 54 53 60 40 0 0 0 0 0 0 The AMR (Adaptative Multirate) speech codec: - offers 8 AMR modes between 4,75 kbits/s and 12,2 kbits/s - is capable of switching its bit rate every 20 ms upon command of the RNC - is located in the UE and in the transcoder (which is located in the CN) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 217
  • Appendix/NBAP elementary procedures NBAP elementary procedures NBAP Functions (see 3GPP 25.433) •Cell Configuration Management. This function gives the CRNC the possibility to manage the cell configuration information in a Node B. •Common Transport Channel Management. This function gives the CRNC the possibility to manage the configuration of Common Transport Channels in a Node B. •System Information Management. This function gives the CRNC the ability to manage the scheduling of System Information to be broadcast in a cell. •Resource Event Management. This function gives the Node B the ability to inform the CRNC about the status of Node B resources. •Configuration Alignment. This function gives the CRNC and the Node B the possibility to verify that both nodes has the same information on the configuration of the radio resources. •Measurements on Common Resources. This function allows the CRNC to initiate measurements in the Node B. The function also allows the Node B to report the result of the measurements. •Radio Link Supervision. This function allows the CRNC to report failures and restorations of a Radio Link. •Compressed Mode Control [FDD]. This function allows the CRNC to control the usage of compressed mode in a Node B. •Measurements on Dedicated Resources. This function allows the CRNC to initiate measurements in the NodeB. The function also allows the NodeB to report the result of the measurements. •DL Power Drifting Correction (FDD). This function allows the CRNC to adjust the DL power level of one or more Radio Links in order to avoid DL power drifting between the Radio Links. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 218
  • Appendix/RANAP elementary procedures RANAP elementary procedures RANAP Functions (some of them (see 3GPP 25.413)) •Relocating serving RNC. This function enables to change the serving RNC functionality as well as the related Iu resources (RAB(s) and Signalling connection) from one RNC to another. •Overall RAB management. This function is responsible for setting up, modifying and releasing RABs. •Release of all Iu connection resources. This function is used to explicitly release all resources related to one Iu connection. •SRNS context forwarding function. This function is responsible for transferring SRNS context from the RNC to the CN for intersystem forward handover in case of packet forwarding. •Controlling overload in the Iu interface. This function allows adjusting the load in the Iu interface. •Sending the UE Common ID (permanent NAS UE identity) to the RNC. This function makes the RNC aware of the UE's Common ID. •Paging the user. This function provides the CN for capability to page the UE. •Transport of NAS information between UE and CN. This function has three sub-classes: •Controlling the security mode in the UTRAN. This function is used to send the security keys (ciphering and integrity protection) to the UTRAN, and setting the operation mode for security functions. •Controlling location reporting. This function allows the CN to operate the mode in which the UTRAN reports the location of the UE. •Data volume reporting function. This function is responsible for reporting unsuccessfully transmitted DL data volume over UTRAN for specific RABs. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 219
  • Appendix/RSNAP elementary procedures RSNAP elementary procedures RSNAP Functions (some of them (see 3GPP 25.423)) •Radio Link Management. This function allows the SRNC to manage radio links using dedicated resources in a DRNS; •Physical Channel Reconfiguration. This function allows the DRNC to reallocate the physical channel resources for a Radio Link; •Radio Link Supervision. This function allows the DRNC to report failures and restorations of a Radio Link; •Compressed Mode Control [FDD]. This function allows the SRNC to control the usage of compressed mode within a DRNS; •Measurements on Dedicated Resources. This function allows the SRNC to initiate measurements on dedicated resources in the DRNS. The function also allows the DRNC to report the result of the measurements; •DL Power Drifting Correction [FDD]. This function allows the SRNC to adjust the DL power level of one or more Radio Links in order to avoid DL power drifting between the Radio Links; •CCCH Signalling Transfer. This function allows the SRNC and DRNC to pass information between the UE and the SRNC on a CCCH controlled by the DRNS; •Paging. This function allows the SRNC to page a UE in a URA or a cell in the DRNS; •Common Transport Channel Resources Management. This function allows the SRNC to utilise Common Transport Channel Resources within the DRNS (excluding DSCH resources for FDD); •Relocation Execution. This function allows the SRNC to finalise a Relocation previously prepared via other interfaces. © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 220
  • Related Documentation Abbreviations and Acronyms © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 221
  • Related documentation English - WCDMA for UMTS, Harri Holma and Antti Toskala, Wiley 2000, ISBN 0 471 72051 8 - UMTS Mobile communications for the future, Wiley 2001, ISBN 0 471 49829 7 - Alcatel Telecommunications Review, 1st Quarter 2001 (“Find your way with 3G”) - 3GPP specifications: ftp:/ftp.3gpp.org/ / Specs/ Francais - UMTS les réseaux mobiles de troisième génération, Editions Eyrolles 2001 (translation of “WCDMA for UMTS” ) - UMTS les origines, l'architecture, la norme, Pierre Lescuyer, Editions Dunod 2001, ISBN 2 10 005195 4 - Revue des Télécommunications d’Alcatel , 1er trimestre 2001 (entièrement consacrée à la 3G) © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 222
  • Abbreviations and Acronyms (1) AAL ACELP ADN ALCAP AMR ATM ATM Adaptation Layer Algebraic Code Excited Linear Prediction Abbreviated Dialling Number Access Link Control Application Part Adaptive Multi Rate Asynchronous Transfer Mode BCCH Broadcast Control Channel BCH BHCA BER BLER BMC BM-IWF Broadcast Channel Busy Hour Call Attempts Bit Error Rate Block Error Rate Broadcast / Multicast Control Broadcast Multicast InterWorking Function Base Station Controller Base Station (sub)System Base Transceiver Station Customized Application for Mobile Enhanced Logic Call Control BSC BSS BTS CAMEL CC © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U CCCH Common Control Channel DCCH Dedicated Control Channel DCH DHO DHT DRAC DRNC DS DSCH DTCH Dedicated Channel Diversity HandOver Diversity HandOver Trunk Dynamic Resource Allocation Control Drift RNC Direct Sequence Downlink Shared Channel Dedicated Traffic Channel CCTrCH CDMA CDR CN CPCH CRNC CS CTCH DCA Coded Composite Transport Channel Code Division Multiple Access Call Detail Record Core Network Common Packet Channel Controlling RNC Circuit Switched Common Traffic Channel Dynamic channel Allocation Page 223
  • Abbreviations and Acronyms (2) EDGE ERAN Enhanced Data rates for GSM Evolution EDGE Radio Access Network (all-IP) FACH Forward Access Channel FBI FDD FDD-DS FDD-MC FER FP FTP GERAN GGSN GPRS GSM GSN GTP GTP-U HO HPLMN FeedBack Information Frequency Division Duplex FDD-Direct Sequence (FDD1) FDD-Multiple Carrier (FDD2) Frame Error Rate Frame Protocol File Transfer Protocol GSM/EDGE Radio Access Network Gateway GPRS Support Node General Packet Radio Service Global System for Mobile Communications GPRS Support Node (ie SGSN or GGSN) GPRS Tunneling Protocol GPRS Tunneling Protocol-User Plane HandOver Home PLM © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U IETF IMEI IMSI IP IR ISDN L1,L2,L3 LA LCS LLC LQC M3UA MAC MBS MC MExE MM MSC MSP Internet Engineering Task Force International Mobile Equipment Identity International Mobile Subscriber Identity Internet Protocol Incremental Redundancy Integrated Services Digital Network Layer 1, Layer 2, Layer 3 Location Area Location Services Logical Link Control Link Quality Control SS7 MTP3 User Adaptation layer Medium Access Control Multi-standard Base Station Multiple Carrier Mobile Execution Environment Mobility Management Mobile-services Switching Center Multiple Subscriber Profile Page 224
  • Abbreviations and Acronyms (3) MTP3 Message Transfer Part (broadband) MTP-3B Message Transfer Part level 3 NAS Non Access Stratum NBAP Node-B Application Part ODMA Opportunity Driven Multiple Access OSA Open service Architecture OTDOA-IPDL Observed Time Difference of Arrival Idle Period Downlink OVSF Orthogonal Variable Spreading Factor PCCH Paging Control Channel PCH PDA PDC PDP PDU PLMN PRACH Paging Channel Personal Digital Assistant Personal Digital Cellular (2G Japan) Packet Data Protocol Protocol Data Unit Public Land Mobile Network Physical Random Access Channel © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U PS QOS QPSK RA RAB Packet Switched Quality Of Service Quadrature Phase Shift Keying Routing Area Radio Access Bearer RACH Random Access Channel RAN RANAP RB RL RLC RNC RNS RNSAP RNTI RRC RRM Radio Access Network RAN Application Part Radio Bearer Radio Link Radio Link Control Radio Network Controller Radio Network Sub-System RNS Application Part Radio Network Temporary Identity Radio Resource Control Radio Resource Management Page 225
  • Abbreviations and Acronyms (4) SAP SAT SDU SF SGSN SHO SIR SMS SPU SRNC SSCOP Service Access Point SIM Application Toolkit Service Data Unit Spreading Factor Serving GPRS Support Node Soft HandOver Signal to Interference Ratio Short Message Service Signaling Processing Unit Serving RNC Service Specific Connection Oriented Protocol SSCP Signaling Connection Control Part STM Synchronous Transfer Mode TC Transcoder TCP Transport Control Protocol TD-CDMA Time Division & CDMA TDD Time Division Duplex TDMA Time Division Multiple Access © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U TF TFC TFCI TFCS TFS TMSI TPC UDP UICC UMTS USIM USSD URA URAN USB UTRAN Transport Format Transport Format Combination Transport Format Combination Indicator Transport Format Combination Set Transport Format Set Temporary Mobile Station Identity Transmission Power Control User Datagram Protocol UMTS Integrated Circuit Card Universal Mobile Telecommunication System UMTS Subscriber Identity Card Unstructured Supplementary Service Data UTRAN Registration Area UMTS Radio Access Network (ETSI) Universal Radio Access Network (3GPP) Universal Serial Bus UMTS Terrestrial Radio Access Network Page 226
  • Abbreviations and Acronyms (5) VC VHE VoIP VP WAP W-CDMA WIM Virtual Channel Virtual Home Environment Voice over IP Virtual Path Wireless Application Protocol Wideband Code Division Multiple Access WAP Identity Module © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 227
  • Abbreviations and Acronyms (Standard Organizations) 3GPP 3GPP2 3GIP ANSI ARIB CWTS ETSI IETF IMT ITU T1 TIA TTA TTC UWCC W3C 3rd Generation Partnership Project (WCDMA) 3rd Generation Partnership Project 2 (cdma2000) 3rd Generation partnership for Internet Protocol American National Standard Institute (USA) Association of Radio Industries and Business (Japan) China Wireless Telecommunication Standard group European Telecommunication Standard Institute Internet Engineering Task Force International Mobile Telecommunication International Telecommunication Union Committee T1 telecommunication of the ANSI (USA) Telecommunication Industry Association (USA) Telecommunication Technology Association (Korea) Telecommunication Technology Committee (Japan) Universal Wireless Communications Committee World Wide Web Consortium © Alcatel University - 8AS 90171 0004 VT ZZA Ed. E.A.U Page 228