Why evolving from 2G to 3G networks? And what does this evolution imply?
High Data Transmission Rates The bit rate targets have been specified according to the Integrated Services Digital Network (ISDN). Indeed, the 144-kbps data rate provides the ISDN 2B+D channel, the 384-kbps provides the ISDN H0 channel and the 1920-kbps provides the ISDN H12 channel. 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. Typically, for fast mobile, voice + 144kbps data are provided for high mobility (car speeds, etc.) in outdoor environment. For slow mobile, 384kbps are provided for limited mobility (pedestrian, etc.). For non mobile, 2Mbps are provided for stationary terminals in indoor environment. Flexibility to Introduce New Services Variable bit rates are used to offer &quot;Bandwidth on Demand&quot; (BoD) and it should be possible to multiplex on the same connection services with different quality requirements (speech, video, etc.). Note that different backward compatibility requirements influence the technology applied to 3G systems.
Let's now consider how radio networks have evolved from 2G to 3G.
GSM systems have evolved in 4 ways: GPRS, EDGE, UMTS and HSDPA/HSUPA. General Packet Radio Service (GPRS) GPRS is an evolution of GSM systems using the already existing BSS with additional packet control functions and a new packet Core Network. Enhanced Data rates for GSM Evolution (EDGE) EDGE is deployed in existing GPRS networks (2.5G) by adding new transceiver equipment in the Base Stations. EDGE for 3G will be the (G)ERAN solution. EDGE Adaptations IS-136 specifics to EGPRS will provide TDMA networks with 3G service and convergence path. Universal Mobile Telecommunications System (UMTS) UMTS is one of the IMT-2000 3G standards, specified by ETSI as an evolution of GSM systems. Different releases are forecast: R’99, R4, R5, R6. High-Speed Packet Access (HSPA) High-Speed Downlink Packet Access ( HSDPA ) increases DL speeds to over 14Mbps at the physical layer and 10Mbps at the application layer whereas High-Speed Uplink Packet Access ( HSUPA ) increases UL speeds typically up to 2Mbps and up to 5.7 Mbps based on Network and UE capabilities.
4 Coding Schemes are used in GPRS: CS1 with 9.05kbps (8.8kbps), CS2 with 13.4kbps (11.2kbps), CS3 with 15.6kbps (14.8kbps) and CS4 with 21.4kbps (17.6kbps). A GPRS backbone network is added between the BSS and the existing packet data networks (X.25, Internet, etc.). BSS is used for voice and data. It serves 2 network nodes: the MSC/VLR, for Circuit-Switched services (A interface) and the GPRS backbone network, for GPRS (Gb interface). Among the 3 new network entities, we find the Packet Control Unit (PCU) that handles the Um interface low layer functions (Radio Link Control and Medium Access Control protocols, Multiplexing, Scheduling, Power control). Then the Serving GPRS Support Node (SGSN) acting as an interface to the BSSs, manages GPRS mobility, encryption, paging and charging. Finally, the Gateway GPRS Support Node (GGSN) interfaces the packet data networks.
Data Rates Up to 384kbps per carrier is forecast, but physically 473kbps would be possible using Modulation and Coding Scheme 9 (MCS9) on 8 Time Slots. 9 Modulation and Coding Schemes: MCS1: 9.05kbps (8.8kbps) (GMSK) MCS2: 13.4kbps (11.2kbps) (GMSK) MCS3: 15.6kbps (14.8kbps) (GMSK) MCS4: 21.4kbps (17.6kbps) (GMSK) MCS5: (22.4kbps) (8PSK) MCS6: (29.6kbps) (8PSK) MCS7: (44.8kbps) (8PSK MCS8: (54.4kbps) (8PSK) MCS9: (59.2kbps) (8PSK) Solutions One solution is the 2.5G with Enhanced GPRS (E-GPRS). E-GPRS is a simple upgrade of existing equipment (2.5G). GSM release 99 is completed and approved by 3GPP (see later in the document) in December 99. The other solution is the 3G with the GSM EDGE Radio Access Network (GERAN). (G)ERAN is an all-IP network. Note: Evolium™ BTSs are ready for both solutions.
GSM EDGE Radio Access Network (GERAN) connects a mobile station toward the GSM or UMTS core network. GERAN is characterized by a 3G technology, an all-IP solution keeping only one plane for both data and control and the use of the Iu interface (RANAP protocol).
What is the role of IMT-2000 in the standardization of radio networks?
Several groups are working to facilitate the development of global specifications for 3G systems: the 3rd Generation Partnership Project (3GPP) specifies the UTRA radio interface, the 3rd Generation Partnership Project 2 (3GPP2) specifies the CDMA2000 radio interface and the 3G.IP specifies the all-IP core network. ETSI - European Telecommunications Standards Institute T1 - Standard Committee T1 Telecommunications: Committee T1 develops technical standards and reports regarding interconnection and interoperability of telecommunications networks. It is sponsored by the Alliance for Telecommunications Industry Solutions (ATIS) and is accredited by the American National Standards Institute (ANSI). ARIB - Association of Radio Industries and Businesses, Japan TTA - Telecommunications Technology Association, Korea TTC - Telecommunication Technology Committee, Japan TIA - Telecommunications Industry Association, USA ANSI - American National Standards Institute, USA ANSI-41 - American National Standard ANSI/TIA/EIA-41 UWCC - Universal Wireless Communications Committee provides standardization input for UWC-136 that goes to TIA and ETSI CRs. Internet Sites http://www.3GPP.org/ http://www.3GIP.org/ http://www.umts-forum.org/ http://www.etsi.org/
IMT-DS for Direct Sequence is also called UMTS FDD (Wideband-CDMA). IMT-TC for Time Code is also called UMTS TDD (Wideband-CDMA + TDMA). IMT-MC for Multi Carrier is also called CDMA2000 (Multicarrier-CDMA). IMT-SC for Single Carrier is also called EDGE (UWC-136 TDMA). There are 4 radio accesses. UMTS supports 2 CDMA radio modes. The first mode is FDD-DS (Frequency Division Duplex) using Wideband Code Division Multiple Access (W-CDMA with Direct Sequence (*)) for wide coverage and capacity. This mode is also called FDD1. The second mode is Time Division Duplex (TDD) using Time Division & Code Division Multiple Access (TD-CDMA) for intensive downlink interactive services. Another type of radio access is CDMA2000 (for ANSI-41 territories, USA, Americas, Part of Asia) supporting one CDMA radio mode which is FDD-MC (Frequency Division Duplex) using Wideband Code Division Multiple Access (W-CDMA with Multi-Carrier (**)). This mode is also called FDD2. The last radio access is EDGE (UWC-136) for the 3rd generation of D-AMPS network. (*) Direct Sequence - The modulated information-bearing signal is directly modulated by a digital, discrete-time, discrete-valued code signal. The resulting signal modulates the wideband carrier. (**) Multi Carrier - The multicarrier approach has been proposed since it might provide an easier overlay with the existing CDMA systems. 2 kinds of core networks interface the radio subsystems. The first core network, MAP for 3G (FDD1 and TDD), is an extension of GSM network. There is probably no market for FDD2. The second core network, ANSI-41 for CDMA2000 (FDD2) is an extension of CDMAOne network (All ANSI-41). There are some applications possible for TDD mode and also some possibilities for FDD1 if a new spectrum is allocated.
GSM leads the world’s total market with more than 65% of market share and 392 GSM networks on-air developed in 147 countries (Jan 2001). GSM subscribers are in constant evolution with more than 80% in 2 years leading to 435M subscribers (Jan2001), what corresponds to 1 new subscriber every 2s. The part of GSM subscribers is 41% in Europe (255M) and 20% in Asia-Pacific (110M). For information, in 1999, the total market (including analog systems) represented 41.8 B$ (US & Canada = 8.9 B$ Western Europe = 8.8 B$ China = 4.8 B$ Japan = 4.6 B$). 2005 data users forecast was 1.2 Billion worldwide (8%~282 MSbs in Asia/Pacific, 83%~224 MSbs in the US and 91%~409 MSbs in Europe).
Let's now shortly turn towards the 3GPP recommendations that specify the UTRA radio interface.
Now, let's move on to the services and applications supplied in UMTS networks.
Let's begin this section with the description of a user equipment.
Functionally speaking, the User Equipment (UE) is composed of the Mobile Equipment (ME) and the UMTS Subscriber Identity Module (USIM). UMTS Subscriber Identity Module (USIM) The role of the USIM is very similar to that of the SIM in GSM. Indeed, it is used to store subscriber identity, subscription data, authentication and ciphering keys as well as authentication algorithms. Its security as well is improved compared to GSM with a mutual authentication between the card and the network. A USIM contains the following information: language, application directory, Directory, IMSI MSISDN, TMSI PTMSI, security keys, SMS parameters, service access, temporary id LAI/RAI, etc. 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 IMT-2000 terminals with the same card. UMTS Integrated Circuit Card (UICC) The UICC is similar to an SIM card in GSM with the same size (either OSI or plug-in). It may contain one or several USIMs 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. USIM and IC card requirements are specified in TS 21.111.
Mobility Evolution for the Combined GSM/UMTS Network UMTS has been designed for services to be maintained when the user moves from UMTS to GSM/GPRS/EDGE. Radio mobility is allowed between the two networks and the supporting system procedures are well defined in the standards. This means that a dual-mode terminal may move seamlessly between the UMTS and GSM networks. Most UMTS terminals are in fact dual-mode GSM/UMTS devices capable of operating in three or more frequency bands.
There are two possible approach options to access services through the Mobile Equipment: integrated or distributed. With the integrated approach , 1 handset is able to perform all functions, like most of the concept phones today. So, the hanset is a tool for multimedia users as it is large, touch sensitive, with high quality color screen, CPU and memory. The handset includes an open OS allowing development of specific and vertical application, an integrated camera for video transmission, a high quality audio & video playback and full-web browsing capabilities (XML/XHTML based). With the distributed approach , 1 handset is used both for voice & WAP, or voice only. The handset also has a bluetooth connection to other devices. Bluetooth Story 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 desktop devices… In February 1998, 5 companies (Ericsson, Nokia, IBM, Toshiba and Intel) formed a Special Interest Group (SIG). The Bluetooth system is operating in the 2.4GHz Industrial Scientific Medicine (ISM) band. In a vast majority of countries around the world, the range of this frequency band is 2400 - 2483.5MHz. The equipment is classified into 3 power classes: class1 = 100mW (20dBm), class 2 = 2.5mW (4dBm) , class 3 = 1mW (0dBm). Internet Sites: http://www. bluetooth.com
Which types of services can a subscriber access in a UMTS network?
From the subscriber point of view, the use of the Mobile Internet can be split into 3 categories of services. The first category, Always-on , includes applications such as Mobile Office (E-mail, Agenda, Database Access, etc.) or Vertical Application (traffic management, health, etc.) In the second category, the Media one, we find the following applications: Directories (Yellow pages, etc.), Transportation (Flight/train Schedule, etc.), News (general, specific), Music, Games and Location services (dependent on the location of the mobile station). The third category is dediacted to M-Commerce. This category includes physical applications (e.g., On-line shopping) and non-physical applications (On-line banking, Ticketing, Auction, etc.).
Conversational Adaptive Multi-Rate (AMR) speech service: 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 4.75kbps. 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. It operates on 20ms speech frames (160 samples per frames corresponding to an 8-kHz sampling frequency). The coding scheme is called Algebraic Code Excited Linear Prediction (ACELP). H.324 (originally specified for PSTN) should be used for video in CS connections. On the other hand, H.323 and IETF architecture (IETF SIP) are candidates for PS connections. Streaming The data transfer has to be processed as a continuous stream. These applications are typically asymmetrical. Interactive Location-based services: at the moment, UMTS specifies that it will provide location information to an accuracy of 50m. Different positioning methods are specified such as the cell-coverage-based, Observed Time Difference of Arrival-Idle Period Downlink (OTDOA-IPDL) or the Network-Assisted GPS. Within this traffic class, we also find computer games (sometimes graded in the conversational class due to end-to end delay) and Web browsing. Background The delay may reach a few seconds or even minutes with applications such as e-mail delivery, Short Message Service (SMS). The corresponding radio access bearer parameters are traffic class (conversational, streaming, etc.), transfer delay (ms), maximum bit rate (kbps), guaranteed bit rate (kbps), delivery order, maximum SDU size (octets), SDU error ratio, residual bit error ratio, delivery of erroneous SDUs and traffic handling priority. The parameter values comply with Recommendation 23.107.
Now, let me take you through the UMTS architecture.
In this section, we will first describe the functions and the architecture of the UTRAN. Then, we will look in detail at the different architectures of the core network defined by 3GPP. Finally, we will recap the network protocols used on the Iu interface.
Do you know what the role of UTRAN is in the UMTS architecture and what it is made up of?
Functions Related to Radio Resource Management and Control Radio resource configuration and operation Radio environment survey Combining/splitting control Radio bearer connection setup and release (Radio Bearer Control) Allocation and deallocation of Radio Bearers [TDD - Dynamic Channel Allocation (DCA)] Radio protocols function RF power control & setting [TDD - Timing Advance] Radio channel coding & decoding & channel coding control Initial (random) access detection and handling CN Distribution function for Non-Access Stratum messages Functions Related to Mobility: Handover and SRNS relocation Radio Channel Ciphering and Deciphering: Ciphering is carried out inside the RNC. Functions Related to Overall System Access Control: Admission control, congestion control and system information broadcasting. Functions Related to Broadcast and Multicast Services (Broadcast/Multicast Interworking Function BM‑IWF): Broadcast/Multicast Information Distribution & Flow Control and Cell Broadcast Service Status Reporting. Only Broadcast is applicable for Release 99.
UTRAN Architecture The UTRAN is composed of several Radio Network Subsystems (RNSs). One RNS is linked with the Core Network using the Iu interface. The RNS consists of 1 Radio Network Controller and several Nodes B attached to it through the Iub interface. Role of the RNC The RNC controls the radio resources in its domain (all the attached Nodes B) as well as the User Equipment connection. The RNC also provides services to the Core Network. The RNC can be considered as the Service Access Point (SAP) for the CN. The Node B is a logical node responsible for radio transmission / reception in one or more cells to/from the UE. The logical node terminates the Iub interface towards the RNC. It also participates in radio resource management. Serving RNC The serving RNC is the RNC that provides the Iu connection between a UE and the Core Network. There is 1 Serving RNC for each UE connected to the Core Network. Drift RNC The drift RNC is the RNC which provides radio resources to a UE. One UE may have 0, 1 or more DRNCs. In the situation described in the above diagram, it is possible to change the link with the Core Network (Iu) so that the Drift RNC (DRNC) becomes the Serving RNC (SRNC) (or equivalent: DRNS becomes SRNS). This procedure is called an &quot;SRNS relocation&quot;.
Let's discover now the functions of the core network within a UMTS network and the different architectures defined by 3GPP.
The Core Network Domain consists of the physical entities which provide support for the network features and telecommunication services. The support provided includes functionality such as the management of user location information, control of network features and services, the transfer (switching and transmission) mechanisms for signaling and for user generated information.
Mobile Switching Center / Visitor Location Register (MSC/VLR): a switch and an associated database for Circuit-Switched (CS) services. Gateway MSC (GMSC): a gateway between UMTS PLMN and external CS networks. Serving GPRS Support Node (SGSN): similar to MSC/VLR but for Packet-Switched (PS) services. Gateway GPRS Support Node (GGSN): similar to GMSC but for PS Services. Home Location Register (HLR): a database for user service profiles and location (CS and/or PS). CN Architecture In R’99, the CN is composed of 2 domains: Circuit Switched and Packet Switched. The entities are similar to those of the GSM networks for CS domain (MSC/VLR, GMSC) and respectively those of the GPRS networks for PS domain (SGSN and GGSN). Limitations: CS up to 64 kbps, PS up to 384kbps
The CN R4 can be connected to UTRAN through Iu-CS and Iu-PS interfaces and to BSS through A and Gb interfaces. The MSC can be implemented in two different entities: the MSC Server, handling only signaling, and the CS-MGW, handling user’s data. An MSC server and a CS-MGW make up the full functionality of an MSC. The MSC server mainly comprises the call control and the mobility control parts of the MSC. It also contains a VLR to hold the mobile subscriber’s service data and CAMEL-related data. The GMSC server mainly comprises the call control and mobility control part of a GMSC. The MSC and GMSC servers control the parts of the call state that pertain to connection control for media channels in a CS-MGW. Over the reference point between MSC servers, the network-network based call control is performed. Examples of this are ISUP or an evolvement of ISUP for Bearer Independent Call Control (BICC). These signaling protocols can be transported over IP. A CS-MGW may terminate bearer channels from a circuit-switched network and media streams from a packet network (e.g., RTP streams in an IP network). Over Iu, the CS-MGW may support media conversion, bearer control and payload processing (e.g., codec, echo canceller, conference bridge) for support of different Iu options for CS services (AAL2/ATM based as well as RTP/UDP/IP based). IP or ATM backbone is used to interconnect CS-MGWs.
The CN R5 can be connected to UTRAN through Iu-CS and Iu-PS interfaces and to GERAN through A/Iu-CS and Gb/Iu-PS interfaces. The Home Subscriber Service ( HSS) is the master database for a given user. It is the entity containing the subscription-related information to support the network entities actually handling calls/sessions. The HSS consists of the 3 functionalities. First, the IP multimedia functionality provides support to control functions of the IP Multimedia Subsystem (IMS) such as the Call Session Control Function (CSCF). It is needed to enable subscriber's access to the IMS services. Then the HSS consists of the subset of the HLR functionality required by the PS domain. Finally, the subset of the HLR functionality required by the CS domain, if it is desired, enables subscriber's access to the CS domain or to support roaming to legacy GSM/UMTS CS domain networks. The IP Multimedia CN (IM CN) subsystem comprises all CN elements for provision of multimedia services. This includes the collection of signaling and bearer-related network elements. The IM CN subsystem should enable the convergence of, and access to, voice, video, messaging, data and web-based technologies for the wireless user, and combine the growth of the Internet with the growth in mobile communications. The complete solution for the support of IP multimedia applications consists of terminals, GERAN or UTRAN radio access networks, GPRS evolved core network, and the specific functional elements of the IM CN subsystem described in this technical specification. The IP multimedia subsystem uses the PS domain to transport multimedia signaling and bearer traffic. The PS domain maintains the service while the terminal moves and hides these moves from the IP multimedia subsystem. The IP multimedia subsystem is independent of the CS domain although some network elements may be common with the CS domain. This means that it is not necessary to deploy a CS domain in order to support an IMS-based network.
The CSCF can act as Proxy CSCF (P-CSCF), Serving CSCF (S-CSCF) or Interrogating CSCF (I-CSCF). The P-CSCF is characterized by being the first contact point for the UE within the IM subsystem. The S-CSCF actually handles the session states in the network. The I-CSCF is mainly the contact point within an operator’s network for all connections destined to a subscriber of that network operator. The Media Gateway Control Function (MGCF) controls the parts of the call state that pertain to connection control for media channels in an IM-MGW. It communicates with CSCF and selects the CSCF depending on the routing number for incoming calls from legacy networks. The MGCF also performs protocol conversion between ISUP and the IM subsystem call control protocols. An IM-MGW may terminate bearer channels from a circuit switched network and media streams from a packet network (e.g., RTP streams in an IP network). The IM-MGW may support media conversion, bearer control and payload processing (e.g. codec, echo canceller, conference bridge). It Interacts with the MGCF for resource control, owns and handles resources such as echo cancellers and may need to have codecs. The Breakout Gateway Control Function (BGCF) selects the network in which PSTN breakout is to occur. If the BGCF selects that the breakout is to occur in the same network, then the BGCF shall select an MGCF which will be responsible for the interworking with the PSTN. If the breakout is in another network, the BGCF will forward this session signaling to a BGCF, or an MGCF, depending on configuration, in the other network.
Now, let's study the technical aspects of the UMTS radio transmission.
In this section, we will see what the underlying principles of UMTS are compared to those of GSM. Then we will define the main characteristics of radio resources and we will explain how these resources are managed.
Do you know what CDMA is and how it works?
Orthogonality Criterion &quot;u and V are orthogonal&quot; means u.v = 0 and u.u = 1.
FDD Mode All mobiles in a given area are using the same 5-MHz channel at the same time. Coding used allows to extract the right signal. One band is used for uplink traffic, another one for downlink traffic. TDD Mode A 5-MHz channel is always used but mobiles will get access to it only every 1/15 period of time (10ms). The same band will be used for uplink and downlink traffic but timeslots are different.
2 radio modes to get always best efficiency: UTRA-FDD (W-CDMA) for wide and urban coverage and UTRA-TDD (TD-CDMA) for intensive downlink interactive services. The Frequency Division Duplex (FDD) mode provides continuous W-CDMA coverage. The Time Division Duplex (TDD) mode provides specific solutions for asymmetric traffic and dedicated indoor systems, in line with the market requirements (by 2003).
The 850/900MHz band can now be used in the UMTS network. This allows major improvement such as extend coverage in rural areas. It means that we can reduce the number of site vs. UMTS 2100MHz. We can also simplify Engineering and sites installation with GSM 900 sites reuse. And finally we can enable a cost effective & fast deployment in low capacity areas. Another major improvement is the possibility to increase the end user QoS in urban and suburban areas thanks to a better in-building penetration gain with UMTS 900 compared to UMTS 2100.
High-Speed Downlink Packet Access (HSDPA) has been standardized by 3GPP R5. It aims at increasing significantly the downlink data throughput up to 14.4 Mega bits per second at the physical layer. It is based on techniques such as Adaptive Modulation and Hybrid ARQ to achieve such high data throughput and peak rates and, reduce delay . HSDPA relies on a new type of transport channel, the HS-DSCH, which is terminated in the Node B. HS-DSCH is applicable only on PS domain RABs.
HSDPA is using shared transport channels : High-Speed Downlink Shared Channels (HS-DSCHs). It is easy to understand that shared channels are more cost-efficient than Dedicated CHannels (DCHs). But there are other advantages. Indeed, DCHs have been designed predominantly for circuit-switched services, that is to say for a conversational Quality of Service class: constant bit rate and stringent real-time requirements. DCHs are not cost-efficient for packet services and are difficult to optimize. Shared channels have been introduced as well to fit with packet services that are downlink oriented with a “bursty” nature and less sensitive to delay than circuit-switched services.
High-Speed Uplink Packet Access (HSUPA) is introduced by 3GPP in release 6 with the aim to improve the Uplink (UL) data rate. HSUPA is characterized by a high data rate for PS calls over the UL air interface.
At present, let's define the main characteristics of radio resources.
Spreading is applied to the physical channels. It consists of two operations. The first is the channelization operation, which transforms every data symbol into a number of chips, thus increasing the bandwidth of the signal. The number of chips per data symbol is called the Spreading Factor (SF). The second operation is the scrambling operation, where a scrambling code is applied to the spread signal.
All the users transmit on the same 5-MHz carrier at the same time and interfere with each other. At the receiver, the users can be separated by means of quasi-orthogonal codes. Quasi-orthogonal means that it is not necessary to have primary colors at the receiver to separate the user. Red and orange for example can also be distinguished. Orthogonality between the codes is impossible to maintain after transfer over the radio interface (multi-path on DL, UEs not synchronized on UL). In Uplink, there is 1 scrambling code per UE among 224 codes and 1 channelization code per UE. There are several codes only when SF=4. The UE automatically selects its channelization code according to the transmission bit rate. In Downlink, there is 1 primary scrambling code per cell among 512 codes, 1 channelization code per common channel and 1 channelization code per UE, within a code tree. The code is selected according to the maximum bit rate and to the coding scheme.
2 radio modes to get always best efficiency: UTRA-FDD (W-CDMA) for wide and urban coverage, and UTRA-TDD (TD-CDMA) for intensive downlink interactive services. The Frequency Division Duplex (FDD) mode provides continuous W-CDMA coverage. The Time Division Duplex (TDD) mode provides specific solutions for asymmetric traffic and dedicated indoor systems, in line with the market requirements (by 2003).
We have just reviewed the radio resources. How are these radio resources managed then?
The objectives of the soft handover are to avoid cut-off at change of cell, to reduce uplink interference generated in the network and to reduce effects of shadowing in downlink. The decision (RNC) to add or remove a cell from the active set of the UE is based on measurements reports (the active set of the UE is the set of Nodes B the UE is simultaneously connected to). In CDMA, it is recommended to have 20 to 30% of UEs in soft handover.
Step 1: The UE makes a call. Step 2: Softer HO. Step 3: Soft HO. Step 4: On UL, the Serving RNC (SRNC1) 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. The Drift RNC (DRNC2) performs the routing of information from/to the Serving RNC. There may be up to 4 Drift RNC(s) per UE. Step 5: Temporary state. Step 6: SRNS relocation: change of Iu interface. The former DRNC (DRNC2) becomes SRNC (SRNC2) for that UE, former SRNC (SRNC1) no longer plays a role in the call.
What is the near-far problem and how does power control affect it? Power control is required in CDMA systems. One of the reasons is to solve the near-far problem. Consider two Mobile users RED and GREEN. If GREEN is closer to the Node B than RED then the node B won’t be able to receive the signal from RED properly because of interferences generated by GREEN. Power control is required to lower down transmitting power from GREEN and to limit the interferences. More generally, the power control is necessary to optimize the radio resources.
Open Loop Power Control The UL open loop power control (function located in both the UTRAN and the UE) sets the initial power of the UE, i.e. at random access. The function uses UE measurements and broadcast cell/system parameters as input. The DL open loop power control (function located in both the UTRAN and the UE) sets the initial power of downlink channels. It receives downlink measurement reports from the UE. Closed Loop Power Control The inner loop power control consists of an estimation of SIR and a comparison with the SIR target, Node B commands in order to decrease or increase the MS power and a fast power control (1500Hz), quicker than the fast Raleigh fading for moderate mobile speeds. The UL inner loop power control sets the power of the uplink dedicated physical channels. In FDD, it is a closed loop process. It receives the quality target from UL outer loop power control and quality estimates of the uplink dedicated physical control channel. The power control commands are sent on the downlink dedicated physical control channel to the UE. This function is located in both the UTRAN and the UE. In TDD, it is an open loop process. It receives the quality target from the UL outer loop power control and uses the quality target and quality estimates of downlink channels to set the transmit power. This function is located in the UE. The DL inner loop power control sets the power of the downlink dedicated physical channels. It receives the quality target from DL outer loop power control and quality estimates of the downlink dedicated physical control channel. The power control commands are sent on the uplink dedicated physical control channel to the UTRAN. This function is located in both the UTRAN and the UE. The outer loop power control consists of the adjustment of the SIR target by the RNC depending on the transmission quality (Block Error Rate).
The cell radius decreases because only the mobiles close to the transmitter (with strong signal) are able to retrieve correct information when the interference increases.
This is the end of this e-learning training. Thank you for your attention.
1 From 2G to 3G 1.1 2G Limitations / 3G Requirements
1.1 2G Limitations / 3G Requirements 1.1.1 What Are the 2G Limitations? 2G limitations C U SOON SMS => Lack of compatibility <ul><ul><li>Rate 9.6kbps </li></ul></ul>Waste of radio resource (before GPRS) Not adapted for new services such as video streaming Large number of 2G systems
1.1 2G Limitations / 3G Requirements 1.1.2 What Are the 3G Requirements? 3G requirements <ul><li>Worldwide roaming </li></ul><ul><li>Single system for the following environments: </li></ul><ul><ul><li>cellular </li></ul></ul><ul><ul><li>satellite </li></ul></ul><ul><ul><li>office </li></ul></ul><ul><ul><li>residential </li></ul></ul><ul><ul><li>High speed: </li></ul></ul><ul><ul><li>144-384kbps: full coverage and mobility </li></ul></ul><ul><ul><li>2Mbps: Limited coverage and mobility </li></ul></ul>Better spectrum efficiency Flexibility to introduce new services
1.2 2G-to-3G Evolution 1.2.1 Evolution of the Radio Access Network 2G RAN <ul><li>BSS GSM </li></ul><ul><li>Up to 160kbps </li></ul><ul><li>Internet services </li></ul>R’97/98/99 (GSM) <ul><li>BSS EDGE </li></ul><ul><li>Up to 384kbps </li></ul><ul><li>Internet services </li></ul>R’99 (GSM) Radio technique FDMA + TDMA E-GPRS GPRS 3G RAN <ul><li>GERAN EDGE </li></ul><ul><li>Up to 384kbps </li></ul><ul><li>Multimedia </li></ul><ul><li>VoIP </li></ul>R5 (3GPP) EDGE CDMA <ul><li>UTRAN UMTS </li></ul><ul><li>Up to 384kbps </li></ul><ul><li>Multimedia </li></ul><ul><li>AMR voice </li></ul>R99’/R3/R4 (3GPP) UMTS <ul><li>UTRAN 3G/HSDPA </li></ul><ul><li>Up to 10Mbps DL </li></ul><ul><li>Multimedia </li></ul><ul><li>AMR voice then VoIP </li></ul>HSDPA R5 (3GPP) R6 (3GPP) <ul><li>UTRAN 3G/HSUPA </li></ul><ul><li>Typical: 2 Mbps UL </li></ul><ul><li>Multimedia </li></ul><ul><li>VoIP </li></ul>HSUPA
1.2 2G-to-3G Evolution 1.2.2 General Packet Radio Service (GPRS) BSS with PCU (GSM + GPRS) VMSC/VLR CS GMSC BSS POTS PS SGSN GPRS backbone i GGSN IP network HLR
1.2 2G-to-3G Evolution 1.2.3 Enhanced Data Rates for GSM Evolution (EDGE) New radio modulation 2 generations GERAN 3G Insertion in UMTS solutions Up to 384kbps E-GPRS 2.5G Evolution of GSM radio part
1.2 2G-to-3G Evolution 1.2.4 GSM EDGE Radio Access Network (GERAN) BSC GSM GSM EDGE GSM EDGE GSM EDGE BSC Iu Iu UMTS core network (All IP)
2 Services and Applications 2.1 User Equipment
2.1 User Equipment 2.1.1 Description User Equipment (UE) Cu Mobile Equipment (ME) Hello world 1 2 3 6 9 5 8 7 4 0 * # UMTS UICC USIM 2 GSM access SIM USIM 1 UMTS Node B GSM BTS Hello world 1 2 3 6 9 5 8 7 4 0 * # GSM
2.1 User Equipment 2.1.2 Some Characteristics no, A-GPS, OTDOA Location 32kbps to 2048kbps Transmission rate class 1 to 4 (GSM and/or UMTS) Supported classmarks 1 to 4 (radio transmission power) Power class 2100, 1900MHz Frequency band FDD or TDD Radio technology 768kbps 384kbps 128kbps 64kbps 32kbps Down 2048kbps 768kbps 384kbps 128kbps 64kbps 32kbps UP Transmission rate class 0.126W 0.25W 0.5W 2W 4 3 2 1 Power class Tx and Rx on GSM and UMTS Plus simultaneous transmission TYPE 4 Rx on GSM and UMTS Plus simultaneous reception TYPE 3 Automatic switch Measurements on other network TYPE 2 Manual Switch No measurement on other network TYPE 1 Supported classmark
2.1 User Equipment 2.1.3 How to Access Services? <ul><li>Strong consumer expectation for mobile multimedia </li></ul><ul><li>Excellent tool for vertical market applications </li></ul><ul><li>Operator / Manufacturer Flagship product (NTT DoCoMo) </li></ul>distributed integrated Probably 2 in 1
2 Services and Applications 2.2 Types of Services
2.2 Types of Services 2.2.1 Applications Always-on applications User Equipment = always-on device User Equipment = information device User Equipment = store Media applications Purchasing: Merchant M-Commerce applications Infotainment: Service Provider Communicating: Users/Machines Hello world 1 2 3 6 9 5 8 7 4 0 * #
2.2 Types of Services 2.2.2 QoS Classes <ul><li>AMR speech service </li></ul><ul><li>Video telephony (IETF multimedia architecture): </li></ul><ul><ul><li>CS: H.324 </li></ul></ul><ul><ul><li>PS: H.323 </li></ul></ul><ul><li>E-mail delivery </li></ul><ul><li>SMS </li></ul><ul><li>Etc. </li></ul><ul><li>Location-based services </li></ul><ul><li>Computer games </li></ul>streaming interactive background conversational Traffic Class Data integrity sensitive - + Delay sensitive - + Video on demand
Objectives <ul><li>Objectives: </li></ul><ul><li>To be able to describe the functional architecture of the UMTS network. </li></ul><ul><li>Content: </li></ul><ul><li>3.1 UTRAN </li></ul><ul><li>3.2 Core Network </li></ul><ul><li>3.3 Protocols on Iu </li></ul>
3.2 Core Network 3.2.1 Functions Core Network functions Management of user location information Control of network features and services Communication with RANs and other CNs Transfer mechanisms (switching and transmission) for signaling and user data
3.2 Core Network 3.2.2 3GPP R'99/R3 Architecture CS domain PSTN PS domain IP network UTRAN Iu-CS Iu-PS Gn Gi D Gc C Gr MAP ISUP SS7 network GTP IP network GGSN SGSN Gs HLR MSC/VLR GMSC
3.2 Core Network 3.2.3 3GPP R4 Architecture BICC PS domain Iu-PS IP network SGSN GGSN UTRAN HLR Iu-CS PSTN MSC/VLR MSC/VLR User data Signaling MSC server & VLR CS-MGW GMSC server CS-MGW IP, ATM BSS Edge A, Gb,
Objectives <ul><li>Objectives: </li></ul><ul><li>To be able to describe the UMTS and CDMA basic principles. </li></ul><ul><li>Content: </li></ul><ul><li>4.1 CDMA Principles </li></ul><ul><li>4.2 Radio Resources: Frequency, Time, Power/Code </li></ul><ul><li>4.3 Radio Resource Management </li></ul>
4.1 CDMA Principles 4.1.1 Multiple Access Technique FDMA TDMA CDMA User1 User2 User3 User1 User2 User3 User1 User2 User3 Time Frequency Power Time Frequency Power Time Frequency Power / Code
4.1 CDMA Principles 4.1.2 CDMA Characteristics <ul><li>The entire bandwidth is used by each user at the same time: </li></ul><ul><li>Intra-cell interference. </li></ul><ul><li>User orthogonality is achieved by codes. </li></ul><ul><li>1 frequency on all the cells, so the entire bandwidth is used in each cell: </li></ul><ul><li>Inter-cell interference. </li></ul><ul><li>Cell orthogonality is achieved by codes. </li></ul>
4.1 CDMA Principles 4.1.4 CDMA Frequency Range FDD mode Wide CDMA paired bands (2 x 60MHz) TDD mode TD/CDMA (Time Division) unpaired bands (35MHz) 1900 1980 2010 2025 1920 TDD TDD FDD UL FDD DL MSS UL MSS DL 2170 2200 2110
4.1 CDMA Principles 4.1.5 UMTS 900/850MHz <ul><li>Site count reduction </li></ul><ul><li>Better in-building penetration gain </li></ul><ul><li>GSM site reuse </li></ul>More coverage Better indoor penetration <ul><li>Our R&D Driver of UMTS 900Hz Specifications at 3GPP </li></ul><ul><li>UMTS/HSDPA + 900/850MHz = Winning Combination </li></ul>
4.1 CDMA Principles 4.1.6 HSDPA: What For? <ul><li>HSDPA Standardized by 3GPP R5 </li></ul><ul><li>HSDPA is designed to: </li></ul><ul><li>Increase the Downlink data throughput over the air interface (theoretical peak user bit rate = 14.4Mbps). </li></ul><ul><li>Provide instantaneous high data rates in the PS domain (e.g., Internet browsing, video on demand). </li></ul><ul><li>HSDPA could be deployed in both FDD and TDD modes. </li></ul>DL UL
4.1 CDMA Principles 4.1.7 HSDPA: Better Use of Resources HSDPA 3G with a High Speed DL Shared Channel Classical 3G with Dedicated Channel A shared channel is much more efficient than a dedicated channel to carry bursty packet traffic .
4.1 CDMA Principles 4.1.8 HSUPA: What For? <ul><li>HSUPA Standardized by 3GPP R6 </li></ul><ul><li>HSUPA standardized by 3GPP R6 is designed to increase the Uplink data throughput over the air interface (theoretical peak user bit rate = 5.7Mbps). </li></ul>3GPP Release 6 Throughput & Capacity HSUPA Uplink Dedicated Channels High Throughputs R99 = 384 kbps UL Cat. 5 UE: 2 Mbps UL Cat. 6 UE: 5.7 Mbps UL
4 UMTS Basic Principles 4.2 Radio Resources: Frequency, Time, Power/Code
4.2 Radio Resources: Frequency, Time, Power/Code 4.2.1 Definition SAME E-TACTIC Channelization Code Scrambling Code S: Signal level N: Noise level f Power N 0 Spread Signal S’ S chip 0 1 0011 0010 Channelization code example: Spreading factor = 4 UE1 0 1 1011 1010 UE2 1 Spreading - CATS EAT MICE n Chips n Chips 2 Scrambling S T A C - E E A T M I C f Power S bit N 0 SIR S
4.2 Radio Resources: Frequency, Time, Power/Code 4.2.2 Multiple Access A B Noise! Channelization Bit chips scrambling Mixed chips modulation UE1 UE2 Node B
4.2 Radio Resources: Frequency, Time, Power/Code 4.2.3 FDD and TDD Modes Characteristics Up to 2Mbps Up to 2Mbps Bearer capability Convolutional, Turbo Convolutional, Turbo Channel coding scheme 16 to 1 (UL and DL) <ul><li>DL: 512 to 4 </li></ul><ul><li>UL: 256 to 4 </li></ul>Spreading factor Multi-slot, multi-code Variable spreading factor, multi-code Multi-rate/variable-rate scheme Synchronization needed Not Needed Inter-BS synchronization 15 15 Slots per frame 10ms 10ms Frame length 3.84Mcps 3.84Mcps Chip rate Nominal 5MHz Nominal 5MHz Bandwidth <ul><li>UL:1900-1920MHz </li></ul><ul><li>DL: optional 2010-2025MHz </li></ul><ul><li>UL: 1920-1980MHz </li></ul><ul><li>DL: 2110-2170MHz </li></ul>Frequency bands Time division Frequency division Duplex scheme TDMA with CDMA in time slots Direct-Sequence CDMA Multiple access scheme TDD FDD
4 UMTS Basic Principles 4.3 Radio Resource Management
4.3 Radio Resource Management 4.3.1 Soft Handover (1/2) Core network Iu Iu Iub Iub RNC1 RNC2 Node B2 Node B3 drift serving Iur
4.3 Radio Resource Management 4.3.2 Soft Handover (2/2) Core network Iub Iub Iu Iub Iur Iu Iub Node B1 Node B2 Node B3 Node B4 RNC1 RNC2 1 2 3 4 S D 5 D S 6 S
4.3 Radio Resource Management 4.3.3 Power Control (1/2) <ul><li>Power Control Issue </li></ul><ul><li>Near-far effect in uplink </li></ul><ul><li>Minimize the interference level </li></ul>Node B Hello world 1 2 3 6 9 5 8 7 4 0 * #
4.3 Radio Resource Management 4.3.4 Power Control (2/2) SIR > SIR target ? Open loop Closed loop Outer loop Inner lo op Tx power estimation SIR target adjustment Node B Node B SIR > SIR target ? TPC command RNC SIR target Hello world 1 2 3 6 9 5 8 7 4 0 * #
4.3 Radio Resource Management 4.3.5 Radio Resources <ul><li>Concentric Coverage : The coverage is determined by the uplink interference level. </li></ul><ul><li>Soft capacity : The capacity is determined by the downlink interference level and the code orthogonality. </li></ul><ul><li>Load of the cell : trade-off capacity/coverage ( breathing cells). </li></ul>
Standards: Series 21 to 23 <ul><ul><li>21-Series: Requirements Specifications </li></ul></ul><ul><ul><li>These specifications are often transient and contain requirements leading to other specifications. They may become obsolete when technical solutions have been fully specified. They could then, e.g., be replaced by reports describing the performance of the system. They could be deleted without replacement or be kept for historical reasons but turned into background material. When found necessary and appropriate, the transient or permanent nature of a requirement specification may be expressed in its scope. </li></ul></ul><ul><ul><li>2 2-Series: Service Aspects </li></ul></ul><ul><ul><li>Specifications in this series specify services, service features, building blocks or platforms for services (a service feature or service building block may provide certain generic functionality for the composition of a service, including the control by the user; a platform may comprise a single or more network elements, e.g. UIM, mobile terminal, auxiliary system to the core network etc.). Stage-1 aspecs that are felt appropriate belong to this series. Reports defining services which can be realized by generic building blocks etc. also belong to this series. </li></ul></ul><ul><ul><li>2 3-Series: Technical Realization </li></ul></ul><ul><ul><li>This series mainly contains stage-2 specifications (or specifications of a similar nature describing interworking over several interfaces, the behavior in unexceptional cases, etc.). </li></ul></ul>
Standards: Series 24 to 26 <ul><ul><li>24-Series: Signaling Protocols (UE - CN Network) </li></ul></ul><ul><ul><li>This series contains the detailed and bit-exact stage-3 specifications of protocols between Mobile Station/User Equipment and the Core Network. </li></ul></ul><ul><ul><li>2 5-Series: UTRA Aspect </li></ul></ul><ul><ul><li>25.100-series: UTRA radio performance aspects (radio performance of UTRAN). </li></ul></ul><ul><ul><li>25.200-series: UTRA radio aspects ((physical) layer 1 of UTRA). </li></ul></ul><ul><ul><li>25.300-series: UTRA radio interface architecture, layer 2 and layer 3 aspects (layer 2/3 of the UMTS radio). </li></ul></ul><ul><ul><li>25.400-series: UTRA network aspects (Iub, Iur and Iu interfaces within UTRAN). </li></ul></ul><ul><ul><li>2 6-Series </li></ul></ul><ul><ul><li>Speech codecs and other codecs (video, etc.). </li></ul></ul>
Standards: Series 27 to 31 <ul><li>27-Series: Data </li></ul><ul><li>Functions needed to support data applications. </li></ul><ul><li>29-Series: Signaling Protocols (NSS) </li></ul><ul><li>This series contains the detailed and bit-exact stage-3 specifications of protocols within the Core Network. </li></ul><ul><li>30-Series: Program Management </li></ul><ul><li>This series contains the 3GPP 3rd Generation Mobile System, project plans / project work program and standalone documents for major work items. </li></ul><ul><li>31-Series: UIM </li></ul><ul><li>This series specifies the User Identity Module (UIM) and the interfaces between UIM and other entities. </li></ul>
Standards: Series 32 to 35 <ul><li>32-Series: Operation and Maintenance </li></ul><ul><li>This series defines the application of TMN for the 3GPP 3rd Generation Mobile System and other functions for operation, administration and maintenance of a 3rd Generation Mobile System network. </li></ul><ul><li>33-Series: Security Aspects </li></ul><ul><li>This series contains specifications of security functions. </li></ul><ul><li>34-Series: Test </li></ul><ul><li>This series contains test specifications. </li></ul><ul><li>35-Series: Algorithms </li></ul><ul><li>This series contains the specifications of encryption algorithms for confidentiality and authentication, etc. </li></ul>
Self-assessment on the Objectives <ul><li>Please be reminded to fill in the form Self-Assessment on the Objectives for this module </li></ul><ul><li>The form can be found in the first part of this course documentation </li></ul>