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Wireless Communication_Airport seminar 25_June_2014


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Wireless Communication_Airport seminar 25_June_2014

  1. 1. Agenda • What is Wireless Communication • 1G (AMPS- Analog cellular USA) • 2G (GSM- TDMA) • 3G (CDMA, CDMA2000 and etc) • 4G (WIMAX, LTE- OFDMA)
  2. 2.  Communication is the process of exchanging information usually via a common system of symbols  Is the process of exchanging information and ideas. An active process, it involves encoding, transmitting, and decoding intended messages. There are many means of communicating and many different language systems. Speech and language are only a portion of communication... What is communication?
  3. 3. Wireless History  Radio invented in the 1880s by Marconi  Many sophisticated military radio systems were developed during and after WW2  Cellular has enjoyed exponential growth since 1988, with about 4 billion users worldwide today  Ignited the wireless revolution  Voice, data, and multimedia becoming ubiquitous  Use in third world countries growing rapidly  Wifi also enjoying tremendous success and growth  Wide area networks (e.g. Wimax) and short-range systems other than Bluetooth (e.g. UWB) less successful  Ancient Systems: Smoke Signals, Carrier Pigeons, …
  4. 4. WHY WIRELESS COMMUNICATION? • Freedom from wires. • No bunch of wires running from here and there. • “Auto Magical” instantaneous communication without physical connection setup e.g.- Bluetooth, Wi-Fi. • Global coverage • Communication can reach where wiring is infeasible or costly • E.g.- rural areas,buildings,battlefield,outerspace. • Stay connected,flexiblity to connect multiple devices.
  5. 5. WHAT IS WIRELESS COMMUNICATION? • Transmitting/receiving voice and data using electromagnetic waves in open space. • The information from sender to receiver is carried over a well defined channel. • Each channel has a fixed frequency bandwidth & capacity(bit rate). • Different channels can be used to transmit information in parallel and independently.
  6. 6. Communication system model8
  7. 7. Source Coding Objective Q: Real time transmission of medical ultrasound images is usually needed for further diagnosis. Due to its large size it demands very high bandwidth therefore compression is required. Determine the required data rate to transmit Ultrasound stream of images with frame rate of 15 frames per second, each frame is 352 x 288 pixels with each pixel requiring 8 bits, and no data compression is used. Do you think a wireless communication channel with 64 kbps can carry this multimedia signal? Answer The required data rate to transmit the ultrasound stream of images is: 352*288*8*15 = 12.165 Mbits/sec. No, 64 kbps channel can not carry this data, therefore we need compression
  9. 9. Types Of wireless communication: • Point to point- • Multi-point - • Broadcast 13
  10. 10. Basic Waves involved in communication • The 3 basic waves are -Radio Waves -Infrared Waves- -Micro Waves 14
  11. 11. TYPES OF WIRELESS COMMUNICATION? RADIO TRANSMISSION:- easily generated, Omni- directional , travel long distance , easily penetrates buildings. • PROBLEMS:- frequency dependent , relatively low bandwidth for data communication , tightly licensed by government. MICROWAVE TRANSMISSION:- widely used for long distance communication , relatively inexpensive. • PROBLEMS:- don’t pass through buildings , weather and frequency dependent.
  12. 12. TYPES CONTINUED…. INFRARED AND MILIMETER WAVES:- Widely used for short range communication , unable to pass through solid objects , used for indoor wireless LANs , not for outdoors.
  13. 13. Advantages and disadvantages of wireless communication • Advantages: – Working professionals can work and access Internet anywhere and anytime without carrying cables or wires wherever they go. This also helps to complete the work anywhere on time and improves the productivity. – A wireless communication network is a solution in areas where cables are impossible to install (e.g. hazardous areas, long distances etc.) – Wireless networks are cheaper to install and maintain • Disadvantages: – Has security vulnerabilities – High costs for setting the infrastructure – Unlike wired communication, wireless communication is influenced by physical obstructions, climatic conditions, interference from other wireless devices
  14. 14. Current Wireless Systems Cellular Systems Wireless LANs WIMAX Satellite Systems Bluetooth Ultrawideband radios Zigbee radios LTE and LTE-Advance
  15. 15. What is Electromagnetic Waves? - Travel at speed of light (c=3*10^8 m/s) -Higher frequency means higher energy photons. -The higher the energy photon the more penetrating is the radiation. 19
  16. 16. What is Electromagnetic Waves? 20
  17. 17. What is Electromagnetic Waves? 21
  18. 18. What is Electromagnetic Waves? 22
  19. 19. What is Electromagnetic Spectrum? 23
  20. 20. What is Electromagnetic Spectrum? 24
  21. 21. radio wave 25
  22. 22. How are radio waves produced? - Radio waves are produced by Passing an oscillating electric current through a long wire called an aerial. -The frequency of the radio wave produced is the same as the frequency of the oscillating current. 26
  23. 23. Infrared WAVE 27 Infrared radiation is a form of electromagnetic radiation that lies between microwaves and visible light on the electromagnetic spectrum. Electromagnetic waves having frequencies from 300 GHz to 400 THz are also called IR waves or Infrared waves.It also use in optical fibre as well.
  24. 24. How it is transmitted? • IR waves are used for short range communication and use line of sight propagation. • Infrared waves cannot pass through solid objects, like walls and be easily contained in a room. • They are cheap, easy to build and do not require any government license to use them. • IR waves offer very bandwidth for use. 28
  25. 25. 29 Infrared Waves
  26. 26. Spectrum Regulation • Spectral Allocation in US controlled by FCC (Federal Communication Commision)(commercial) or OSM (defense), in UK by OFCOM • Auctions of spectral blocks for set applications. • Some spectrum set aside for universal use • Worldwide spectrum controlled by ITU-R • Regulation is a necessary evil. Innovations in regulation being considered worldwide, including underlays, overlays, and cognitive radios
  27. 27. US Spectrum allocation today
  28. 28. Design Challenges • Wireless channels are a difficult and capacity- limited broadcast communications medium • Traffic patterns, user locations, and network conditions are constantly changing • Applications are heterogeneous (diverse) with hard constraints that must be met by the network • Energy and delay constraints change design principles across all layers of the protocol stack
  29. 29. Future Generations Rate Mobility 2G 3G 4G 802.11b WLAN 2G Cellular Other Tradeoffs: Rate vs. Coverage Rate vs. Delay Rate vs. Cost Rate vs. Energy Fundamental Design Breakthroughs Needed 802.11n Wimax/3G
  30. 30. Evolution of Current Systems  Wireless systems today 3G Cellular: ~200-300 Kbps. WLANs: ~450 Mbps (and growing).  Next Generation 4G Cellular: OFDM/MIMO 4G WLANs: 802.11 ac / ad  Technology Enhancements Hardware: Better batteries. Better circuits/processors. Link: Antennas, modulation, coding, adaptivity, DSP, BW. Network: Not much: more efficient algorithms and ACKs Application: Soft and adaptive QoS.
  31. 31. Multimedia Requirements Voice VideoData Delay Packet Loss BER Data Rate Traffic <100ms - <100ms <1% 0 <1% 10-3 10-6 10-6 8-32 Kbps 1-100 Mbps 1-20 Mbps Continuous Bursty Continuous One-size-fits-all protocols and design do not work well
  32. 32. Quality-of-Service (QoS) QoS refers to the requirements associated with a given application, typically rate and delay requirements. It is hard to make a one-size-fits all network that supports requirements of different applications. Wired networks often use this approach with poor results, and they have much higher data rates and better reliability than wireless. QoS for all applications requires a cross-layer design approach.
  33. 33. 1- Wireless local area network(WLAN)
  34. 34. Wireless local area network(WLAN) • WLAN connect local computers • Range (100 m) confined region • Break data into packets • Channel access is shared • Backbone internet provides best service • Poor performance in some application like videos • Low mobility
  35. 35. Wireless LAN Standards  802.11b (Old – 1990s)  Standard for 2.4GHz ISM (Industrial, Science and Medical) band (80 MHz)  Direct sequence spread spectrum (DSSS)  Speeds of 11 Mbps, approx. 500 ft range  802.11a/g (Middle Age– mid-late 1990s)  Standard for 5GHz NII band (300 MHz)  OFDM in 20 MHz with adaptive rate/codes  Speeds of 54 Mbps, approx. 100-200 ft range  802.11n (Standard closed in Sept. 2009)  Standard in 2.4 GHz and 5 GHz band  Adaptive OFDM /MIMO in 20/40 MHz (2-4 antennas)  Speeds up to 600Mbps, approx. 200 ft range  Other advances in packetization, antenna use, etc. 802.11ac (Release Dec. 2012)  Also multi-user MIMO 802.11ad (Release Feb. 2014)  Also 60GHz Many WLAN cards have all 3 (a/b/g)
  36. 36. 2- Satellite system ? • Global coverage • Optimized for good transmission • Expensive base stations. • Voice and data transmission • Telecommunication application • GPS , global telephone connection • TV broadcasting , military , weather broadcasting
  37. 37. How communication takes place? Transmitting Signal Received Signal Satellite Transmitting Antenna Receiving Antenna
  38. 38. Satellite Systems  Cover very large areas  Different orbit heights  GEOs (36000 Km) versus LEOs (2000 Km)  Optimized for one-way transmission  Radio (XM, Sirius) and movie (SatTV, DVB/S) broadcasts  Most two-way systems struggling or bankrupt  Global Positioning System (GPS) use growing  Satellite signals used to pinpoint location  Popular in cell phones, PDAs (Personal Digital Assistance), and navigation devices
  39. 39. 3- Bluetooth • Cable replacement RF technology (low cost) • Short range (10m, extendable to 100m) • 2.4 GHz band (crowded) • 1 Data (700 Kbps) and 3 voice channels, up to 3 Mbps • Widely supported by telecommunications, PC, and consumer electronics companies • Few applications beyond cable replacement
  40. 40. 4- Ultrawideband Radio (UWB) UWB is an impulse radio: sends pulses of tens of picoseconds(10-12 s) to nanoseconds (10-9 s) Duty cycle of only a fraction of a percent A carrier is not necessarily needed Uses a lot of bandwidth (GHz) High data rates, up to 500 Mbps 7.5 Ghz of “free spectrum” in the U.S. (underlay) Multipath highly resolvable: good and bad Limited commercial success to date
  41. 41. 5-IEEE 802.15.4 / ZigBee Radios  Low-Rate WPAN (Wireless Personal Area Connectivity)  Uses 2.4 GHz radio frequency  Connects an immense range of simple and high-tech devices for consumer and business.  Data rates of 20, 40, 250 Kbps  Support for large mesh networking or star clusters  Support for low latency devices  CSMA-CA (Carrier Sense MA-Collision Avoidance)channel access  Very low power consumption Focus is primarily on low power sensor networks
  42. 42. Tradeoffs ZigBee Bluetooth 802.11b 802.11g/a 3G UWB Range Rate Power 802.11n
  43. 43. 6- CELLULAR TECHNOLOGY (GSM) Cellular network is a radio-based technology; radio waves are electromagnetic waves that antenna propagate. Most signals are in the 850MHZ, 900MHZ, 1800MHZ, 1900MHZ frequency bands. Mobile radio Transmission system may be classified into: Simplex, Half-Duplex, Full-Duplex. Simplex: One way communication- Paging System. Half-Duplex: Two way communication, but same channel for TX and RX. Push-To-Talk, release-to-listen. Ex: walkie talkies- Applies to TDD system. Full-Duplex: Two way communication in different frequency, simultaneously transmit and receive. Ex: Mobile phone. Applies to FDD system. TDD- Time Division Duplex FDD: Frequency Division Duplex One channel for uplink and down link Separate channel for uplink and downlink ADV: Effective spectrum usage ADV: Suitable for voice communication DIAADV: Time delay DIS ADV: Spectrum usage is high.
  44. 44. • Frequency division duplexing uses two radio channel – Forward channel: base station to mobile user – Reverse channel: mobile user to base station • Time division duplexing shares a single radio channel in time. Forward Channel Reverse Channel
  45. 45. • Communication between the base station and mobiles is defined by the standard common air interface (CAI) – Forward voice channel (FVC): voice transmission from base station to mobile – Reverse voice channel (RVC): voice transmission from mobile to base station – Forward control channels (FCC): initiating mobile call from base station to mobile – Reverse control channel (RCC): initiating mobile call from mobile to base station
  46. 46. GSM Channel Type
  47. 47. MICROWAVE COMMUNICATION Microwave communication requires line of sight and earth towers to transmit information and hence have relatively smaller area coverage. One tower receives a signal it amplifies it and sends it to the next tower. The microwave systems have the capability to carry large amount of data both digital and analogue at high speed and are mostly used for the transmission of telephone and television signals. Advantages: No cables needed. Multiple channels available. Wide bandwidth. Disadvantages: Line-of-sight will be disrupted if any obstacle, such as new buildings, are in the way Signal absorption by the atmosphere. Microwaves suffer from attenuation due to atmospheric conditions. Towers are expensive to build. MW equipment providers: Ericsson Nokia Alcatel Intracom
  48. 48. 3G Cellular Design: Voice and Data  Data is bursty, whereas voice is continuous  Typically require different access and routing strategies  3G “widens the data pipe”:  384 Kbps (802.11n has 100s of Mbps).  Standard based on wideband CDMA  Packet-based switching for both voice and data 3G cellular popular in Asia and Europe  Evolution of existing systems in US (2.5G++)  GSM+EDGE, IS-95(CDMA)+HDR  100 Kbps may be enough  Dual phone (2/3G+Wifi) use growing (iPhone, Google) What is beyond 3G?  3GPP LTE  …
  49. 49. Evolution of Cellular technology
  51. 51. STANDARDS What is STANDARD: Standard is a level of quality, especially one that people think is acceptable. standard is nothing but collection of defined criteria's to asses product ,service or system. Why do we need standards? Standards can be found throughout our daily lives but why do we need them? Products might not work as expected. They may be of inferior quality and incompatible with other equipment, in fact they may not even connect with them. non-standardized products may even be dangerous. Standardized products and services are valuable User 'confidence builders', being perceived as: Safe. Secure. high quality. Flexible. As a result, standardized goods and services are widely accepted, commonly trusted and highly valued.
  52. 52. WIRELESS COMMUNICATION STANDARD ITU-International Telecommunication Union. IEEE- Institute of Electrical and Electronics Engineers. The 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations, known as the Organizational Partners. 3GPP is the standard body behind the (UMTS) that is the 3G upgrade to GSM networks. The 3rd Generation Partnership Project 2(3GPP) is a collaboration between telecommunications associations to make a globally applicable 3G mobile phone system specification within the scope of the ITU's IMT-2000 project. 3GPP2 is the standard body behind the competing 3G standard CDMA2000 that is the 3G upgrade to CDMAONE networks used mostly in the United States. GSM/GPRS/EDGE/W-CDMA is the most widespread wireless standard in the world. A few countries (such as China, the United States, India, South Korea and Japan) use both sets of standards, but most countries use only the GSM family.
  53. 53. STANDARDS What is ITU: International Telecommunication Union. is an agency of the United Nations (UN) whose purpose is to coordinate telecommunication operations and services throughout the world. The ITU sets and publishes regulations and standards relevant to electronic communication and broadcasting technologies of all kinds including radio, television, satellite, telephone and the Internet . It has three sectors: 1.ITU-T Telecommunication Standardization sector It coordinates standards for telecommunications. Ex: GSM, 3G, 4G. 2.ITU-R Telecommunication Radio communication sector. It coordinates standards for radio communications services as well as the international management of the radio frequency spectrum and satellite orbits. Ex: ULTRA-HDTV & 3D-TV 3.ITU-D Telecommunication Development sector. Assists countries in developing and maintaining internal communication operations
  55. 55. Evolution of Cellular technology Generations Definitions/Data rate Features 1G-1980-1990 Analog-14.4Kb/s Voice 2G-1990-2004 Digital narrow band CKT Voice, SMS, Conference calls, Caller ID. 2.5G-GPRS Digital narrow band CKT/Packet data Voice+Data/WAP/MMS 2.75G-EDGE Digital narrow band CKT/Packet data Voice Data/WAP/MMS/Web browsing/Short audio video clips. 3G-2004-13 Digital broadband packet data/Data rate- 200kb/s-2mb/s High speed web/Video conferencing/Navigation/maps 3.5G-HSDPA Digital broadband packet data/Data rate- 8Mkb/s-10Mb/s High speed web/Video conferencing/Navigation/maps Multiplayer gaming 3.75G-HSUPA Digital broadband packet data/Data rate- 1.4Mb/s-5Mb/s High speed web/Video conferencing/Navigation/maps 4G-LTE Digital broadband packet data very high throughput/Data rate-100Mb/s-1Gb/s High quality streaming video/High quality video conferencing.
  56. 56. Evolution of Cellular technology Generations Advantages Disadvantages 1G-1980-1990 Focus on voice Data service non-existent Impossible international roaming. Poor handoff reliability. Large Phone size. 2G-1990-2004 Possibility of wireless data service. More flexible. Unable to handle complex data such as video. Circuit switch network, does not support high data rate results weaker digital signal. 3G-2004-13 Rich multimedia services. More bandwidth and security. High data rate. Expensive service license. Infrastructure for 3G. 4G-LTE(Up coming) Broadband access in remote locations. Higher BW tight network security. Very expensive.
  57. 57. MODULATION TECHNIQUE Modulation: Modulation is the process of superimposing a low frequency signal on high frequency carrier signal. It`s process of mixing a signal with sinusoid to produce a new signal. Will have certain benefits of an un-modulated signal especially during transmission. Modulation is a form of change process where we change the input information into a suitable format for the transmission medium. It`s general technique of shaping a signal to convey a information. Keying : Keying is a family of modulation forms. The goal of keying is to transmit digital signal over an analogue channel. Analog Modulation: AM, FM, PM, QAM, SM, SSB. Digital Modulation: ASK, APSK, CPM, FSK, MFSK, MSK, PSK. Spread spectrum: CSS, DSSS, FHSS.
  58. 58. DIFF-AM FM PM AM FM PM Amplitude of the carrier signal increase or decrease Frequency of the carrier signal increase or decrease Phase of the carrier signal increase or decrease Can Transmit long distance Short Distance FM and PM are inseparably links BW is small BW is high Phase is integral of frequency Poor sound quality Better than AM PM used for digital form of txn Range 535-1705Khz upto 1200 Bps 88-108 Mhz upto 1200-2400Bps ASK+PSK=QAM Impacted with environmental noise Doesn`t degrade linearly with distance While Phase changes Frequency will change and vice-versa Impacted with physical barrier
  59. 59. AM FM PM
  60. 60. MULTIPLEXING TECHNIQUE Multiplexing: Combining multiple stream information for transmission over a shared medium. Several input one output. To combine many signals(voice or data) so they can sent over one transmission medium. De multiplexing: Reverse function of multiplexing. One input several Output. Guard Band: It`s an unused part of the radio spectrum between radio bands. FDM TDM Can be used with analog signal. Can be used with digital signal or analog signal carrying digital data. No.of signal carried signal on same medium. Data from various sources are carried in respective frames. By allocating to each signal a different frequency band. Each frames consists of time slots. Guard bands are used for avoid interference, Each source assigned time slot per frame. Provide much better latency. Sync pulses added to identify the beginning of each frame. Provide much better flexibility.
  61. 61. Frequency Division Multiple Access Frequency is a precious and natural resource. Each mobile is assigned a separate frequency channel for the duration of the call. MS will have one downlink frequency band and one uplink frequency band. Guar band is required to prevent adjacent channel interference.
  62. 62. Time Division Multiple Access TDMA is a type of multiplexing where two or more channel of information are transmitted over the same link by allocating a different time interval for the transmission of each channel. TDMA separates users according to time, it ensures that there will be no interference from simultaneous transmission. Each user is given a specific slot. It`s the only technology that the user has occupied predefined time slots. Only one mobile terminal transmits during each slot.
  63. 63. Access Method: Time Division Multiple Access (TDMA)
  64. 64. Code Division Multiple Access CDMA is a digital wireless air interface and networking standards based on the principle of spread spectrum technology, which allow multiple users to access the system simultaneously on the same carrier frequency. Bandwidth occupied by the signal is much larger than the information transmission rate. Each symbol of bit is transmitted as a larger number of bits using the user specific code – Spreading. Use of orthogonal codes to separate different transmissions. But all users use the same frequency band together.
  65. 65. FDMA CDMA TDMA Differ signals are assigned frequency channel. A channel is a frequency. Users can access the system simultaneously on the same carrier frequency by using SS. Users can access the same frequency spectrum by dividing the time slots. Each channel can be assigned to only one user at a time. By using unique assigned codes users can be occupy the frequency. 2 or more channel of information are transmitted over same link by allocating diff time interval. SS: The signal occupies a BW in excess of the minimum necessary to send the information. FHSS: improves C/I ratio by utilizing many freq channel. And also fading and mmultipath prob. ADV: Make before break connection.” soft hand off” Very high spectral capacity. ADV: “Hard hand off”. Easily adapt data & voice transmission. Users separates by dividing time slots. It ensures no interference. DIS ADV: Channel pollution. There is no international roaming. DIS ADV: “call drop” may occur when moving one to another. EX: AMPS, TACS EX: CDMA 2000-1X RTT, CDMA 2000-1X EVDO EX: GSM
  66. 66. What is GSM GSM stands for Global System for Mobile communication. The European system was called GSM and deployed in early 1990`s. Designed on 900MHZ and 1800MHZ range. It was the first fully digital system utilizing the 900MHZ frequency band. The initial GSM had 200KHZ radio channel s, 8-full rate or 16-half rate TDAM channels per carrier. The GSM makes use of narrowband Time Division Multiple Access (TDMA) technique for transmitting signals. The GSM was developed using digital technology. It has an ability to carry 64 kbps to 120 Mbps of data rates. Presently GSM support more than one billion mobile subscribers in more than 210 countries throughout of the world. The GSM provides basic to advanced voice and data services including Roaming service.
  67. 67. 0 124 0 124 915 MHz 935 MHz 960 MHz890 MHz UPLINK DOWNLINK GSM 900 Frequency Channels
  68. 68. What is CDMA IS-95-Code Division Multiple Access. 824-849MHZ. Each carrier 1.24MHZ. 4 types of logical channel: A pilot, A synchronization, 7 paging, 55 traffic. Channels are separated using different spreading codes. QPSK modulation scheme. 64 orthogonal walsh code are used. It`s used to differentiate between the transmission with in the cell. Using PN offset we can separate the cells
  70. 70. Why GSM? The ETSI group aimed to provide the following through the GSM: Improved spectrum efficiency. International roaming. Low-cost mobile sets and base stations (BSs). High-quality speech. Compatibility with Integrated Services Digital Network (ISDN) and other telephone company services. Support for new services.
  72. 72. GSM ARCHITECTURE The GSM network can be divided into following broad parts: The Mobile station(MS). The Base Station Subsystem(BSS). The Net work Switching Subsystem(NSS).
  73. 73. GSM network areas Cell: Cell is the basic service area: one BTS covers one cell. Each cell is given a Cell Global Identity (CGI), a number that uniquely identifies the cell. Location Area: A group of cells form a Location Area. This is the area that is paged when a subscriber gets an incoming call. Each Location Area is assigned a Location Area Identity (LAI). Each Location Area is served by one or more BSCs. MSC/VLR Service Area: The area covered by one MSC is called the MSC/VLR service area. PLMN: The area covered by one network operator is called PLMN. A PLMN can contain one or more MSCs.
  74. 74. The Mobile Stations(MS) MS is the user’s handset and has two parts. ME+SIM. Mobile Equipment: •Radio equipment •User interface •Processing capability and memory required for various tasks. It provides the air interface to the user in GSM networks.
  75. 75. Basic GSM architectural equation, MS = ME + SIM +
  76. 76. The Mobile Station(MS) Functions of mobile stations: Voice and data transmission and receipt. Frequency and time synchronization. Monitoring of power and signal quality of surrounding cells. Provision of location update even during inactive state. An MS can have any of the following state: IDLE: The MS is ON but a call is not in progress. ACTIVE: The MS is ON and a call is in progress. DETACHED: The MS is OFF.
  77. 77. Network Identities MSISDN: Mobile Station ISDN is registered in the telephone directory and used by the calling party for dialing. Shall not exceed 15 digits. IMSI: International Mobile Subscriber Identity, The IMSI is an unique which is used internationally and used within the network to identify the mobile subscribers. Max 15 digits. TMSI: Temporary Mobile Subscriber Identity. It`s temporary IMSI no. The VLR assigns a TMSI to each mobile subscribers entering the VLR area. Assigned only after successful authentication. TMSI changes on location updation. TMSI is less than 8 digit. MSRN: Mobile Station Roaming Number. It`s temporary identity which is assigned during the establishment of a call to a roaming subs. IMEI: International Mobile Equipment Identity. It`s an unique code allocated to each mobile equipment.
  78. 78. Functions of BSS The BSS composed of TWO parts: The Base Transceiver Station(BTS) The Base Station Controller(BSC). The interface between BSC and BTS is designed as an A-bis interface. The interface between the MSC and the BSS is a standardized SS7 interface (A-interface). The BSS is responsible for all the radio related functions in the system, such as:  Radio communication with the mobile units Handover of calls in progress between cells  Management of all radio network resources and cell configuration data.
  79. 79. Functions of BSC It`s part of BSS system BSC manages the radio resources for one or more BTSs. It handles radio channel setup, frequency hopping and handovers. The function of the BSC is to allocate the necessary time slots between the BTS and MSC. Control of frequency hopping. The BSC is connected to the MSC on one side and to the BTS on the other. Handling of MS connections and performs the intercell handover for MSs moving between BTS in its control. Manage the Handover within BSS area. Knows which mobile stations are within the cell and informs the MSC/VLR about this. Controls several transmitters.
  80. 80. Function of Base Transceiver Station BTS acts as the interface between MS’s (Mobile Station) and the network, by providing radio coverage functions from their antennae. It`s located between the Mobile Station (MS) and the Base Station Controller (BSC). The BTS is basically classified into two types: Indoor & Outdoor. The primary responsibility of the BTS (Base Transceiver Station) is to transmit and receive radio signals from a mobile unit over an air interface. A BTS is usually placed in the center of a cell. Its transmitting power defines the size of a cell. Each BTS has between 1 and 16 transceivers, depending on the density of users in the cell. Encoding, encrypting, multiplexing, modulating, and feeding the RF signals to the antenna. Decoding, decrypting, and equalizing received signals
  81. 81. Cont…. Transcoding and rate adaptation. Voice through full- or half-rate services Trans-coding to bring 13-kbps speech to a standard data rate of 16 kbps and then combining four of these signals to 64 kbps is essentially a part of BTS, though, it can be done at BSC or at MSC.
  82. 82. Functions of Network Switching Subsystem NSS or GSM core network is the component of GSM system that carries out call switching and mobility management functions for mobile phones. It was originally consisted of circuit switched core network used for traditional GSM sevices such as voice call, SMS circuit switch data calls. Now extended with an packet switched data services known as GPRS core network. Main functions of NSS: Call control, charging, mobility management, subscriber data handling. The switching system includes the following functional elements. MSC-Mobile Switching Centre. HLR-Home Location Register. VLR-Visitor Location Register AUC-Authentication Centre EIR-Equipment Identity Register.
  83. 83. Functions of MSC The central component of the Network Subsystem is the MSC. primary functions of an MSC include the following: Switching and call routing: Routing of calls between GSM users and PSTN users. Service provisioning: Supplementary services are provided and managed by a MSC. In addition, the SMS service is handled by MSC’s. Charging: The MSC performs billing on calls for all subscribers based in its areas. When the subscriber is roaming elsewhere, the MSC obtains data for the call billing from the visited MSC. Service provisioning: Gateway to SMS between SMS centers and subscribers. Communication with HLR: The primary occasion on which an MSC and HLR communicate is during the set-up of a call to an MS, when the HLR requests some routing information from the MSC.  Communication with the VLR: Associated with each MSC is a VLR, with which it communicates for subscription information, especially during call set-up and release. Communication with other MSC’s: It may be necessary for two MSC’s to communicate with each other during call setup or handovers between cells belonging to different MSC’s.
  84. 84. Cont….. Control of connected BSC’s: As the BSS acts as the interface between the MS’s and the SS, the MSC has the function of controlling the primary BSS node: the BSC. Each MSC may control many BSC’s, depending on the volume of traffic in a particular MSC service area. An MSC may communicate with its BSC’s during, for example, call set-up and handovers between two BSC’s. Direct access to Internet services: Traditionally, an MSC accessed the Internet nodes of an Internet Service Provider (ISP) via existing networks such as the PSTN. GMSC: It`s node that interconnected two network. EX: Calls to and from one network to another network. Either MS to MS and MS to fixed line service.
  85. 85. Functions of HLR The HLR is a centralized network database that stores and manages all mobile subscriptions belonging to a specific operator. Both VLR and HLR can be implemented in the same equipment in an MSC. Data in HLR: IMSI, MS-ISDN number. Category of MS. Roaming restriction ( allowed or not ). Supplementary services like call forwarding. The information stored includes:  Subscriber identity (i.e. IMSI, MSISDN) . Subscriber supplementary services. Subscriber location information (i.e. MSC service area). Subscriber authentication information.
  86. 86. Functions of VLR It`s always integrated with MSC. VLR database which contains information about subscribers currently being in the service area of the MSC/VLR. The VLR database is temporary, in the sense that the data is held as long as the subscriber is within its service area. When a mobile station roams into a new MSC area, the VLR connected to that MSC will request data about the mobile station from the HLR.  if the mobile station makes a call, the VLR will have the information needed for call setup without having to interrogate the HLR each time. VLR assigns TMSI which keeps on changing. Data in VLR: IMSI & TMSI. MSRN. Location Area. MS category. Authentication Key
  87. 87. Functions of AUC The authentication centre is a protected database. The authentication centre provide security information to the network. AUC is connected to HLR which provides it with authentication parameters and ciphering keys used to ensure network security. To perform subscriber authentication and to establish ciphering procedures on the radio link between the network and MS. Information provided is called a TRIPLET consists of: RAND(Non Predictable Random Number) SRES(Signed Response) Kc(ciphering Key).
  88. 88. Functions of EIR EIR is used for security reasons. The equipment identification procedure uses the identity of the equipment itself (IMEI) to ensure that the MS terminal equipment is valid. This data base stores IMEI for all registered mobile equipments and is unique to every ME. White list : IMEI, assigned to valid ME. Black list : IMEI reported stolen.  Gray list : IMEI having problems like faulty software, wrong make of equipment etc.
  89. 89. Mobile Originating Call A call is originated from a MS as follows, The MS uses RACH (Random Access Channel) to ask for a signaling channel.  The BSC/TRC allocates a signaling channel, using AGCH (Access Grant Channel).  The MS sends a call set-up request via SDCCH (Stand alone Dedicated Control Channel) to the MSC/VLR. Over SDCCH all signaling preceding a call takes place. This includes: Marking the MS as “active” in the VLR The authentication procedure Equipment identification Sending the B-subscriber’s number to the network Checking if the subscriber has the service “Barring of outgoing calls” activated
  90. 90. Cont…. The MSC/VLR instructs the BSC/TRC to allocate an idle TCH. The BTS and MS are told to tune to the TCH. The MSC/VLR forwards the B–number to an exchange in the PSTN, which establishes a connection to the subscriber. If the B-subscriber answers, the connection is established.
  91. 91. GSM Geographical Network Structure
  92. 92. Measurements Made By The Mobile Station
  93. 93. MS Registration & Hand Over
  94. 94. Service Categories  Teleservices: A teleservice allows the subscriber to communicate (usually via voice, fax, data or SMS) with another subscriber.  Bearer services: A bearer service transports speech and data as digital information within the network between user interfaces. For example, a bearer service associated with the speech telephony teleservice is the timeslot assigned to a call on a TDMA frame over the air interface.  Supplementary services: These are additional services that are available by subscription only. Call forwarding is an example of a supplementary service.
  95. 95. Teleservices:  Speech  Emergency calls  SMS Cell Broadcast (SMSCB)  Short Message Services (SMS)  Voice mail  Fax mail
  96. 96. Supplementary Services:  Call forwarding  Barring of calls  Call waiting  Call hold  Multiparty service
  97. 97. Data Services Using your GSM phone to receive and send data is the essential building block leading to widespread mobile Internet access and mobile data transfer. GSM currently has a data transfer rate of 9.6 kbps. New developments that will push up data transfer rates for GSM users are HSCSD (high speed circuit switched data) and GPRS (general packet radio service) are now available.
  98. 98. Transmission Problems  Path Loss  Shadowing  Multipath Fading Rayleigh Fading
  99. 99. Shadowing
  100. 100. Multipath Fading Rayleigh Fading
  101. 101. Solution Solves  Channel Coding bit error rate  Antenna Diversity path loss & shadowing Solutions To Transmission Problems
  102. 102. 7- Wimax (802.16) Wide area wireless network standard System architecture similar to cellular Hoped to compete with cellular OFDM/MIMO is core link technology Operates in 2.5 and 3.5 MHz bands Different for different countries, 5.8 also used. Bandwidth is 3.5-10 MHz Fixed (802.16d) vs. Mobile (802.16e) Wimax Fixed: 75 Mbps max, up to 50 mile cell radius Mobile: 15 Mbps max, up to 1-2 mile cell radius
  103. 103. LTE Introduction 6/25/2014 124 LTE evolution Although there are major step changes between LTE and its 3G predecessors, it is nevertheless looked upon as an evolution of the UMTS / 3GPP 3G standards. Although it uses a different form of radio interface, using OFDMA / SC-FDMA instead of CDMA, there are many similarities with the earlier forms of 3G architecture and there is scope for much re-use.LTE can be seen for provide a further evolution of functionality, increased speeds and general improved performance. WCDMA (UMTS) HSPA HSDPA / HSUPA HSPA+ LTE Max downlink speed bps 384 k 14 M 28 M 100M Max uplink speed bps 128 k 5.7 M 11 M 50 M Latency round trip time approx 150 ms 100 ms 50ms (max) ~10 ms 3GPP releases Rel 99/4 Rel 5 / 6 Rel 7 Rel 8 Approx years of initial roll out 2003 / 4 2005 / 6 HSDPA 2007 / 8 HSUPA 2008 / 9 2009 / 10 Access methodology CDMA CDMA CDMA OFDMA / SC-FDMA In addition to this, LTE is an all IP based network, supporting both IPv4 and IPv6. There is also no basic provision for voice, although this can be carried as VoIP.
  104. 104. Introduction 6/25/2014 125 LTE has introduced a number of new technologies when compared to the previous cellular systems. They enable LTE to be able to operate more efficiently with respect to the use of spectrum, and also to provide the much higher data rates that are being required. OFDM (Orthogonal Frequency Division Multiplex): OFDM technology has been incorporated into LTE because it enables high data bandwidths to be transmitted efficiently while still providing a high degree of resilience to reflections and interference. The access schemes differ between the uplink and downlink: OFDMA (Orthogonal Frequency Division Multiple Access is used in the downlink; while SC-FDMA(Single Carrier - Frequency Division Multiple Access) is used in the uplink. SC-FDMA is used in view of the fact that its peak to average power ratio is small and the more constant power enables high RF power amplifier efficiency in the mobile handsets - an important factor for battery power equipment. MIMO (Multiple Input Multiple Output): One of the main problems that previous telecommunications systems has encountered is that of multiple signals arising from the many reflections that are encountered. By using MIMO, these additional signal paths can be used to advantage and are able to be used to increase the throughput. When using MIMO, it is necessary to use multiple antennas to enable the different paths to be distinguished. Accordingly schemes using 2 x 2, 4 x 2, or 4 x 4 antenna matrices can be used. While it is relatively easy to add further antennas to a base station, the same is not true of mobile handsets, where the dimensions of the user equipment limit the number of antennas which should be place at least a half wavelength apart.
  105. 105. LTE specification overview 6/25/2014 126 PARAMETER DETAILS Peak downlink speed 64QAM (Mbps) 100 (SISO), 172 (2x2 MIMO), 326 (4x4 MIMO) Peak uplink speeds (Mbps) 50 (QPSK), 57 (16QAM), 86 (64QAM) Data type All packet switched data (voice and data). No circuit switched. Channel bandwidths (MHz) 1.4, 3, 5, 10, 15, 20 Duplex schemes FDD and TDD Mobility 0 - 15 km/h (optimised), 15 - 120 km/h (high performance) Latency Idle to active less than 100ms Small packets ~10 ms Spectral efficiency Downlink: 3 - 4 times Rel 6 HSDPA Uplink: 2 -3 x Rel 6 HSUPA Access schemes OFDMA (Downlink) SC-FDMA (Uplink) Modulation types supported QPSK, 16QAM, 64QAM (Uplink and downlink)
  106. 106. LTE/SAE Key Features – EUTRAN 1/2 6/25/2014 127 SAE (System Architecture Evolution): With the very high data rate and low latency requirements for 3G LTE, it is necessary to evolve the system architecture to enable the improved performance to be achieved. One change is that a number of the functions previously handled by the core network have been transferred out to the periphery. Essentially this provides a much "flatter" form of network architecture. In this way latency times can be reduced and data can be routed more directly to its destination. SAE Features: Evolved NodeB(eNB) •No RNC is provided anymore •The evolved Node Bs take over all radio management functionality. •This will make radio management faster and hopefully the network architecture simpler IP transport layer •EUTRAN exclusively uses IP as transport layer
  107. 107. LTE/SAE Key Features – EUTRAN 2/2 6/25/2014 128 UL/DL resource scheduling •In UMTS physical resources are either shared or dedicated •Evolved Node B handles all physical resource via a scheduler and assigns them dynamically to users and channels •This provides greater flexibility than the older system QoS awareness •The scheduler must handle and distinguish different quality of service classes •Otherwise real time services would not be possible via EUTRAN •The system provides the possibility for differentiated services Self configuration •Currently under investigation •Possibility to let Evolved Node Bs configure themselves •It will not completely substitute the manual configuration and optimization.
  108. 108. LTE/SAE Key Features – EPC (Evolved Packet Core) 6/25/2014 129 Packet Switched Domain only No circuit switched domain is provided If CS applications are required, they must be implemented via IP Only one mobility management for the UE in LTE. 3GPP (GTP) or IETF (MIPv6) option The EPC can be based either on 3GPP GTP protocols (similar to PS domain in UMTS/GPRS) or on IETF Mobile IPv6 (MIPv6) Non-3GPP access The EPC will be prepared also to be used by non-3GPP access networks (e.g. LAN, WLAN, WiMAX, etc.) This will provide true convergence of different packet radio access system
  109. 109. LTE/SAE Air Interface 1/3 6/25/2014 130 OFDMA •Downlink multiplexing •Orthogonal Frequency Division Multiple Access •Receiver complexity is at a reasonable level •it supports various modulation schemes from BPSK, QPSK, 16QAM to 64 QAM. SC-FDMA •Uplink multiplexing •Single Carrier Frequency Division Multiple Access, a variant of OFDMA •The advantage against OFDMA to have a lower PAPR (Peak-to-Average Power Ratio) meaning less power consumption and less expensive RF amplifiers in the terminal. 64QAM Modulation
  110. 110. LTE/SAE Air Interface 2/3 6/25/2014 131 MIMO •Multiple Input Multiple Output •LTE will support MIMO as an option, •It describes the possibility to have multiple transmitter and receiver antennas in a system. •Up to four antennas can be used by a single LTE cell (gain: spatial multiplexing) •MIMO is considered to be the core technology to increase spectral efficiency. HARQ •Hybrid Automatic Retransmission on request •HARQ has already been used for HSDPA and HSUPA. •HARQ especially increases the performance (delay and throughput) for cell edge users. • HARQ simply implements a retransmission protocol on layer 1/layer 2 that allows to send retransmitted blocks with different coding than the first one. HARQ Hybrid Automatic Repeat Request
  111. 111. LTE/SAE Air Interface 3/3 6/25/2014 132 Scalable bandwidth • LTE air interface allows to drive cells with 1.4 MHz, 3 MHz, 5 MHz, 10MHz & 20 MHz •This gives the required flexibility for operators to use spectrum allocations not available to a non- scalable wide-band or ultra-wide-band system. DL: OFDMA UL: SC-FDMA scalable
  112. 112. Requirements for LTE Air Interface 6/25/2014 133 DOWNLINK UPLINK HSUPA (Rel6) Target SAE/LTE Peak Bit Rate (Mbps) 5.67 > 50 57 Spectral Efficiency (bps/Hz/cell) 0.26 2..3 times HSUPA 0.67 SC-FDMA (Single Carrier Frequency Division Multiple Access) SC-FDMA is technically close to OFDMA, but is more power efficient OFDMA (Orthogonal Frequency Division Multiple Access) HSDPA (Rel6) Target SAE/LTE Peak Bit Rate (Mbps) 14.4 > 100 144 Spectral Efficiency (bps/Hz/cell) 0.75 3..4 times HSDPA 1.84
  113. 113. LTE/SAE Network Elements 6/25/2014 134 LTE-UE Evolved UTRAN (E-UTRAN) MME S10 S6a Serving Gateway S1-U S11 PDN Gateway PDN Evolved Packet Core (EPC) S1-MME PCRF S7 Rx+ SGiS5/S8 Evolved Node B (eNB) cell X2 LTE-Uu HSS MME: Mobility Management Entity PCRF:Policy & Charging Rule Function SAE Gateway Evolved Node B (eNB) cell LTE-Uu LTE-UE
  114. 114. Evolved Node B (eNB) 6/25/2014 135 Evolved Node B (eNB)cell LTE-Uu LTE-UE •It is the only network element defined as part of EUTRAN. •It replaces the old Node B / RNC combination from 3G. •It terminates the complete radio interface including physical layer. •It provides all radio management functions •An eNB can handle several cells. •To enable efficient inter-cell radio management for cells not attached to the same eNB, there is a inter-eNB interface X2 specified. It will allow to coordinate inter- eNB handovers without direct involvement of EPC during this process. Inter-cell RRM: HO, load balancing between cells Radio Bearer Control: setup, modifications and release of Radio Resources Connection Mgt. Control: UE State Mgmt. MME-UE Connection Radio Admission Control eNode B Measurements Collection and evaluation Dynamic Resource Allocation (Scheduler) eNB Functions IP Header Compression/ de-compression Access Layer Security: ciphering and integrity protection on the radio interface MME Selection at Attach of the UE User Data Routing to the SAE GW. Transmission of Paging Message coming from MME Transmission of Broadcast Info (System info, MBMS)
  115. 115. Mobility Management Entity (MME) 6/25/2014 136 Evolved Node B (eNB) MME Serving Gateway S1-U S1-MME S11 HSS S6a • It is a pure signaling entity inside the EPC. • SAE uses tracking areas to track the position of idle UEs. The basic principle is identical to location or routing areas from 2G/3G. • MME handles attaches and detaches to the SAE system, as well as tracking area updates • Therefore it possesses an interface towards the HSS (home subscriber server) which stores the subscription relevant information and the currently assigned MME in its permanent data base. • A second functionality of the MME is the signaling coordination to setup transport bearers (SAE bearers) through the EPC for a UE. • MMEs can be interconnected via the S10 interface • It generates and allocates temporary ids for UEs Non-Access-Stratum (NAS) Signalling Idle State Mobility Handling Tracking Area updates Security (Authentication, Ciphering, Integrity protection) Trigger and distribution of Paging Messages to eNB Roaming Control (S6a interface to HSS) Inter-CN Node Signaling (S10 interface), allows efficient inter-MME tracking area updates and attaches Signalling coordination for SAE Bearer Setup/Release & HO Subscriber attach/detach Control plane NE in EPC MME Functions
  116. 116. 6/25/2014 137 Packet Data Network (PDN) SAE Gateway MME Serving Gateway S5/S8 PDN SAE Gateway PDN SGi PCRF S7 Rx+ S11 S6a Policy Enforcement (PCEF) Per User based Packet Filtering (i.e. deep packet inspection) Charging Support PDN Gateway Functions IP Address Allocation for UE Packet Routing/Forwarding between Serving GW and external Data Network Mobility anchor for mobility between 3GPP access systems and non-3GPP access systems. This is sometimes referred to as the SAE Anchor function Packet screening (firewall functionality) Lawful Interception support • The PDN gateway provides the connection between EPC and a number of external data networks. • Thus it is comparable to GGSN in 2G/3G networks. • A major functionality provided by a PDN gateway is the QoS coordination between the external PDN and EPC. • Therefore the PDN gateway can be connected via S7 to a PCRF (Policy and Charging Rule Function). • If a UE is connected simultaneously to several PDNs this may involved connections to more than one PDN-GW
  117. 117. Policy and Charging Rule Function (PCRF) 6/25/2014 138 MME Serving Gateway S5/S8 PDN SAE Gateway PDN SGi PCRF S7 Rx+ S11 S6a Charging Policy: determines how packets should be accounted PCRF: Policy & Charging Rule Function QoS policy negotiation with PDN • The PCRF major functionality is the Quality of Service (QoS) coordination between the external PDN and EPC. • Therefore the PCRF is connected via Rx+ interface to the external Data network (PDN) • This function can be used to check and modify the QoS associated with a SAE bearer setup from SAE or to request the setup of a SAE bearer from the PDN. •This QoS management resembles the policy and charging control framework introduced for IMS with UMTS release 6.
  118. 118. Home Subscriber Server (HSS) 6/25/2014 139 MME HSS S6a Permanent and central subscriber database HSS Functions Stores mobility and service data for every subscriber Contains the Authentication Center (AuC) functionality. • The HSS is already introduced by UMTS release 5. • With LTE/SAE the HSS will get additionally data per subscriber for SAE mobility and service handling. •Some changes in the database as well as in the HSS protocol (DIAMETER) will be necessary to enable HSS for LTE/SAE. •The HSS can be accessed by the MME via S6a interface.
  119. 119. LTE/SAE Network Interfaces 6/25/2014 140 LTE-UE Evolved UTRAN (E-UTRAN) MME S10 S6a Serving Gateway S1-U S11 Evolved Packet Core (EPC) S1-MME PDN Gateway PDN PCRF S7 Rx+ SGiS5/S8 Evolved Node B (eNB) cell X2 LTE-Uu HSS MME: Mobility Management Entity SAE Gateway User plane Control Plane Control Plane + User plane
  120. 120. LTE Radio Interface and the X2 Interface 6/25/2014 141 (E)-RRC User PDUs PDCP (ROHC = RFC 3095) RLC MAC LTE-L1 (FDD/TDD-OFDMA/SC-FDMA) TS 36.300 eNB LTE-Uu eNB X2 User PDUs GTP-U UDP IP L1/L2 TS 36.424 X2-UP (User Plane) X2-CP (Control Plane) X2-AP SCTP IP L1/L2TS 36.421 TS 36.422 TS 36.423 TS 36.421 TS 36.420 [currently also in TS 36.300 §20] NAS Protocols Control Plane User Plane TS 36.223 TS 36.331 LTE-Uu Air interface of EUTRAN Based on OFDMA in downlink and SC-FDMA in uplink FDD and TDD duplex methods Scalable bandwidth 1.4MHz to currently 20 MHz Data rates up to 100 Mbps in DL MIMO (Multiple Input Multiple Output) is a major component although optional. X2 Inter eNB interface Handover coordination without involving the EPC X2AP: special signaling protocol During HO, Source eNB can use the X2 interface to forward downlink packets still buffered or arriving from the serving gateway to the target eNB. This will avoid loss of a huge amount of packets during inter-eNB handover.
  121. 121. S1-MME & S1-U Interfaces 6/25/2014 142 MME Serving Gateway S1-MME (Control Plane) S1-U (User Plane) NAS Protocols S1-AP SCTP IP L1/L2 User PDUs GTP-U UDP IP L1/L2 TS 36.411 TS 36.411 TS 36.412 TS 36.413 TS 36.414 TS 36.410 [currently in TS 36.300 §19] eNB S1-MME Control interface between eNB and MME S1flex allows 1 eNB to connect to several MME MME and UE will exchange non-access stratum signaling via eNB through this interface. E.g.: if a UE performs a tracking area update the TRACKING AREA UPDATE REQUEST message will be sent from UE to eNB and the eNB will forward the message via S1-MME to the MME. S1AP:S1 Application Protocol S1-U User plane interface between eNB and serving gateway. It is a pure user data interface (U=User plane). S1flex-U also supported: a single eNB can connect to several Serving GWs. Which Serving GW a user’s SAE bearer will have to use is signaled from the MME of this user.
  122. 122. S10 & S6a Interfaces 6/25/2014 143 S10 Interface between different MMEs Used during inter-MME tracking area updates The new MME can contact the old MME the user had been registered before to retrieve data about identity (IMSI), security information (security context, authentication vectors) and active SAE bearers (PDN gateways to contact, QoS, etc.) Obviously S10 is a pure signaling interface, no user data runs on it. S6a Interface between the MME and the HSS The MME uses it to retrieve subscription information from HSS (handover/tracking area restrictions, external PDN allowed, QoS, etc.) during attaches and updates The HSS can during these procedures also store the user’s current MME address in its database. MME HSS S6a (Control Plane) S6a Appl. SCTP IP L1/L2 DIAMETER TR 29.801 MME S10 (Control Plane) UDP IP L1/L2 GTP-C TR 29.801
  123. 123. S11 & S5/S8 Interfaces 6/25/2014 144 Serving Gateway PDN Gateway PDN Sgi S5/S8 GTP Candidates (Control and User Plane) User PDUs GTP-U UDP IP L1/L2 GTP-C TS 23.401 / TR 29.801 MME UDP IP L1/L2 GTP-C S5/S8 IETF Candidates (Control and User Plane) User PDUs MIPv6 Tunneling Layer IPv4/IPv6 L1/L2 PMIPv6 TS 23.402 / TR 29.801 IPv4 IPv6 S11 Interface between MME and a Serving GW A single MME can handle multiple Serving GW each one with its own S11 interface Used to coordinate the establishment of SAE bearers within the EPC SAE bearer setup can be started by the MME (default SAE bearer) or by the PDN Gateway. S11 (Control Plane) S5/S8 Interface between Serving GW and PDN GW S5: If Serving GW and PDN GW belong to the same network (non-roaming case) S8:If this is not the case (roaming case) S8 = S5 + inter-operator security functions Mainly used to transfer user packet data between PDN GW and Serving GW Signaling on S5/S8 is used to setup the associated bearer resources S5/S8 can be implemented either by reuse of the GTP protocol from 2G/3G or by using Mobile IPv6 with some IETF enhancements.
  124. 124. S7 & SGi Interfaces 6/25/2014 145 PDN Gateway IMS/PDN PCRF S7 (Control Plane) SGi (User Plane) Application UDP or TCP IPv4/IPv6 L1/L2 S7 Application SCTP IP L1/L2 TR 23.401 DIAMETER SGi Interface used by the PDN GW to send and receive data to and from the external data network It is typically either IPv4 or IPv6 based Downlink data coming from the external PDN must be assigned to the right SAE bearer of the right user by analysis of the incoming packet’s IP addresses, port numbers, etc. This interface corresponds to the Gi interface in 2G/3G networks S7 (Also referred as Gx) Interface between PDN GW and PCRF (Policy and Charging Rule Function) It allows: -the PCRF to request the setup of a SAE bearer with appropriate QoS -allows the PDN GW to ask for the QoS of an SAE bearer to setup -to indicate EPC status changes to the PCRF to apply a new policy rule.
  125. 125. Rx+ Interface 6/25/2014 146 Rx+ Interface between PCRF(Policy & Charging Rules Function) and the external PDN network/operators IMS Standardized in 3GPP TS 23.203. Rx+ (Control Plane) PDN Gateway PDN PCRF S7 SGi RX+ Application SCTP IP L1/L2 TR 23.203 DIAMETER
  126. 126. SAE/LTE Interworking with 2G/3G Networks 6/25/2014 147 LTE-UE Evolved UTRAN (E-UTRAN) Evolved Packet Core (EPC) MME S6a Serving Gateway S1-U S11 S1-MME PDN Gateway PDN PCRF S7 Rx+ SGiS5/S8 HSS SGSN S3 UTRAN Iu-PS S4 Evolved Node B (eNB) cell LTE-Uu GERAN Gb Gr GGSN Gn PDN Gi
  127. 127. S3 & S4 Interfaces 6/25/2014 148 S4 (User Plane) SGSN MME Serving Gateway S3 (Control Plane) UDP IP L1/L2 GTP-C TR 29.801 / TS 23.401 UDP IP L1/L2 GTP-U TR 29.801 / TS 23.401 User PDUs S3/S4 Interfaces between EPC and 2G/3G packet switched core network domain They would allow inter-system changes between SAE and 2G/3G The S3 is a pure signalling interface used to coordinate the inter-system change between MME and SGSN The S4 is the user plane interface and it is located between SGSN and Serving SAE GW. These 2 interfaces are based on the Gn interface between the SGSN and the GGSN. This would allow to either forward packet data from EUTRAN via Serving SAE GW to SGSN (and then to GGSN) or from 2G/3G RAN to SGSN to Serving SAE GW to PDN GW.
  128. 128. SAE/LTE Interworking with 3G - Alternative 6/25/2014 149 Evolved UTRAN (E-UTRAN) Evolved Packet Core (EPC) MME S6a Serving Gateway S1-U S11 S1-MME PDN Gateway PDN PCRF S7 Rx+ SGiS5/S8 HSS SGSN S3S4 UTRAN Iu-PS Evolved Node B (eNB) cell LTE-Uu GERAN Gb Gr GGSN Gn PDN Gi S12 Direct Tunnels from Serving GW to RNC (User Plane)
  129. 129. S12 Interface 6/25/2014 150 Serving Gateway UDP IP L1/L2 GTP-U TR 29.801 / TS 23.401 User PDUs UTRAN S12 (User Plane) S12 Interfaces between EPC and 3G Radio access network It would allow inter-system changes between SAE and 3G The S12 is the user plane interface used for tunneling user data directly between the Serving SAE GW and the UTRAN. This would allow to forward packet data from 3G RAN to Serving SAE GW to PDN GW. It is based on the Gn interface between the SGSN and the GGSN and so uses the GTP-U protocol.
  130. 130. SAE/LTE Interworking with cdma2000 Networks 6/25/2014 151 LTE-UE Evolved UTRAN (E-UTRAN) Evolved Packet Core (EPC) MME S6a Serving Gateway S1-U S11 S1-MME PDN Gateway PDN PCRF S7 Rx+ SGiS5/S8 HSS S103 S101 Evolved Node B (eNB) cell LTE-Uu A11 HSGW PDN eHRPD Access Network Cdma2000 Network (eHRPD) S2a
  131. 131. S101 & S103 Interfaces 6/25/2014 152 SGSN S101(Control Plane) UDP IP L1/L2 S101-APeHRPD Access Network S103 (User Plane) Serving Gateway (LTE) UDP IP L1/L2 User PDUs HSGW (cdma2000) GRE S101/S103 Interfaces between EPC and cdma2000 They would allow inter-system changes between LTE and cdma2000 The S101 is a pure signaling interface used to coordinate the inter-system change between MME and SGSN The S103 is the user plane interface and it is located between the Serving GW and the HSGW.
  132. 132. MIMO 6/25/2014 153 MIMO stands for Multiple Input Multiple Output. It is a key technology to increase a channel’s capacity by using multiple transmitter and receiver antennas. The propagation channel is the air interface, so that transmission antennas are handled as input to the channel, whereas receiver antennas are the output of it. The very basic ideas behind MIMO have been established already 1970 , but have not been used in radio communication until 1990. MIMO is currently used in 802.11n, 802.16d/e to increase the channel capacity.
  133. 133. Downlink Peak Bit Rate 6/25/2014 154 2x2 MIMO (2 antennas for TX, 2 Antennas for RX) 64QAM Control overhead 7.1% Reference symbol overhead 7.7% 172 Mbps in 20 MHz and 86 Mbps in 10 MHz Resource blocks 6 15 25 50 100 Subcarriers 72 180 300 600 1200 Modulation coding 1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 20 MHz QPSK 1/2 Single stream 0.9 2.2 3.6 7.2 14.4 16QAM 1/2 Single stream 1.7 4.3 7.2 14.4 28.8 16QAM 3/4 Single stream 2.6 6.5 10.8 21.6 43.2 64QAM 3/4 Single stream 3.9 9.7 16.2 32.4 64.8 64QAM 4/4 Single stream 5.2 13.0 21.6 43.2 86.4 64QAM 3/4 2x2 MIMO 7.8 19.4 32.4 64.8 129.6 64QAM 1/1 2x2 MIMO 10.4 25.9 43.2 86.4 172.8 64QAM 1/1 4x4 MIMO 20.7 51.8 86.4 172.8 345.6
  134. 134. Uplink Peak Bit Rate 6/25/2014 155 Single stream transmission with 64QAM assumed Reference symbol overhead 14.3% One resource block for Physical Uplink Control Channel (PUCCH) 85 Mbps in 20 MHz and 42 Mbps in 10 MHz Resource blocks 5 14 24 49 99 Subcarriers 60 168 288 588 1188 Modulation coding 1.4 MHz 3.0 MHz 5.0 MHz 10 MHz 20 MHz QPSK 1/2 Single stream 0.7 2.0 3.5 7.1 14.3 16QAM 1/2 Single stream 1.4 4.0 6.9 14.1 28.5 16QAM 3/4 Single stream 2.2 6.0 10.4 21.2 42.8 16QAM 1/1 Single stream 2.9 8.1 13.8 28.2 57.0 64QAM 3/4 Single stream 3.2 9.1 15.6 31.8 64.2 64QAM 1/1 Single stream 4.3 12.1 20.7 42.3 85.5 64QAM 1/1 V-MIMO (cell) 8.6 24.2 41.5 84.7 171.1
  135. 135. LTE UE Categories 6/25/2014 156 • All categories support 20 MHz • 64QAM mandatory in downlink, but not in uplink (except Class 5) • 2x2 MIMO mandatory in other classes except Class 1
  136. 136. LTE Radio Frames, Slots and Sub frames FDD mode bit rate calculation 6/25/2014 157 The basic EUTRAN Radio Frame is 10 ms long. The EUTRAN Radio Frame is divided into 20 slots, each one 0.5 ms long. Always two slots together form a sub frame. The sub frame (1 ms) is the smallest time unit the scheduler assigns to physical channels. In case of FDD there is a time offset between uplink and downlink transmission. Slot #0 Slot #1 Slot #2 Slot #3 Slot #16 Slot #17 Slot #18 Slot #19 . . . Slot #0 Slot #1 Slot #2 Slot #3 Slot #16 Slot #17 Slot #18 Slot #19 . . . f DL carrier UL carrier radio frame 10 ms radio frame 10 ms subframe 0 subframe 1 subframe 8 subframe 9 subframe 0 subframe 1 subframe 8 subframe 9 DL/ULTimeoffset time
  137. 137. LTE Radio Frames, Slots and Sub frames FDD mode bit rate calculation 6/25/2014 158 If TDD mode is used, sub frame 0 and sub frame 5 must be downlink, all other sub frames can dynamically be used as uplink or downlink period. Slot #0 Slot #1 Slot #2 Slot #3 Slot #16 Slot #17 Slot #18 Slot #19 . . . f time UL/DL carrier radio frame 10 ms subframe 0 subframe 1 subframe 5 subframe 9 . . . Downlink Sub frame Uplink Sub frame
  138. 138. LTE Frame Structure 6/25/2014 159 The number of Symbols per Slot (0.5 ms) could be 6 or 7 depending on the Cyclic Prefix length (Refer to next slide for details)
  139. 139. LTE Slot 6/25/2014 160 The LTE Slot carries: • 7 symbols with short cyclic prefix • 6 symbols with long prefix
  140. 140. OFDM Resource Block for LTE/EUTRAN 6/25/2014 • EUTRAN combines OFDM symbols in so called resource blocks RB. • A single resource block is always 12 consecutive subcarriers during one subframe (2 slots, 1 ms): • 12 subcarriers * 15 kHz= 180 kHz •It is the task of the scheduler to assign resource blocks to physical channels belonging to different users or for general system tasks. •A single cell must have at least 6 resource blocks (72 subcarriers) and up to 110 are possible (1320 subcarriers). frequency time Subcarriers Sub frame 1ms Subcarrier Bandwidth 15kHz Bandwidth 180kHz Slot Slot
  141. 141. 6/25/2014 162 frequency time … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … Slot = 0.5 ms 12subcarriers 6 or 7 Symbols/slot OFDM Symbol Resource Block (RB) • OFDM symbols are arranged in a 2 dimensional matrix called the resource grid: – One axis of the grid is the subcarrier index – The other axis is the time. • Each OFDM symbol has its place in the resource grid. Subframe = 1 ms OFDM resource Grid for LTE/EUTRAN
  142. 142. OFDM resource Grid for LTE/EUTRAN. Channel Estimation 6/25/2014 163 •Channel estimation based on reference symbols. •Interpolation in time and frequency domain •In WCDMA common pilot channel (CPICH) was used for this (together with reference symbols on DCH)
  143. 143. Modulation Schemes for LTE/EUTRAN 6/25/2014 164 •Each OFDM symbol even within a resource block can have a different modulation scheme. •EUTRAN defines the following options: QPSK, 16QAM, 64QAM. Not every physical channel will be allowed to use any modulation scheme: Control channels to be using mainly QPSK. •In general it is the scheduler that decides which form to use depending on carrier quality feedback information from the UE. b0 b1 QPSK Im Re10 11 00 01 b0 b1b2b3 16QAM Im Re 0000 1111 Im Re 64QAM b0 b1b2b3 b4 b5
  144. 144. LTE bit rate calculation 6/25/2014 165 • From the 3gpp specification: -1 Radio Frame = 10 Sub-frame LTE bit rate calculation -1 Sub-frame = 2 Time-slots -1 Time-slot = 0.5 ms (i.e 1 Sub-frame = 1 ms) -1 Time-slot = 7 Modulation Symbols (when normal CP length is used) -1 Modulation Symbols = 6 bits; if 64 QAM is used as modulation scheme Radio resource is manage in LTE as resource grid.... -1 Resource Block (RB) = 12 Sub-carriers Assume 20 MHz channel bandwidth (100 RBs), normal CP Therefore, number of bits in a sub-frame = 100RBs x 12 sub-carriers x 2 slots x 7 modulation symbols x 6 bits = 100800 bits Hence, data rate = 100800 bits / 1 ms = 100.8 Mbps * If 4x4 MIMO is used, then the peak data rate would be 4 x 100.8 Mbps = 403 Mbps. * If 3/4 coding is used to protect the data, we still get 0.75 x 403 Mbps = 302 Mbps as data rate.
  145. 145. 6/25/2014 166 Signalling example, Attach Request UE eNB MME S1AP: INITIAL CONTEXT SETUP REQUEST + EMM ATT_ACC + ESM ACT_DEF_BEAR_REQ S1AP: INITIAL CONTEXT SETUP RESPONSE RRC: RRCConnectionReconfiguration + EMM ATT_ACC + ESM ACT_DEF_BEAR_REQDRB and SRB2 Configuration RRC: RRCConnectionReconfigurationComplete NAS Security Establishment (Authentication + NAS security start) RRC: UECapabilityEnquiry RRC: UECapabilityInformation UE radio capabilities available à DRB can be established S1AP: UE CAPABILITY INFO INDICATION PRACH RANDOM ACCESS PRACH RANDOM ACCESS RESPONSE PUSCH (Msg3) RRC: Connection Request random access procedure RRC: Connection Setup RRC: Connection Setup Complete + EMM ATT_REQ + ESM PDN CONN_REQ S1AP: INITIAL UE MESSAGE + EMM ATT_REQ + ESM PDN CONN_REQ Create Session (S11) RRC: Security Mode Command RRC: Security Command Complete RRC: UL NAS INFO TRANSFER (EMM ATT_COMPLETE + ESM ACT_DEF_BEAR_SUCC S1AP: UL NAS TRANSPORT (EMM ATT_COMPLETE + ESM ACT_DEF_BEAR_SUCC) Step 1: RACH procedure Step 2: SRB1 establishment + initial NAS msg Step 3: NAS security + S1 setup Step 4: RRC security + UE capability Step 5: SRB2 + DRB setup for default bearer
  146. 146. Coexistence (Contemporary) Challenge: Many devices use the same radio band • Technical Solutions: – Interference Cancellation – Smart/Cognitive Radios
  147. 147. Next-Generation Devices Everything Wireless in One Device
  148. 148. Multiradio Integration Challenges • RF Interference • Where to put antennas • Size • Power Consumption Cellular Apps Processor BT Media Processor GPS WLAN Wimax DVB-H FM/XM
  149. 149. 6/25/2014 170 layer-Part-III References
  150. 150. 6/25/2014 171 tutorial.php transport-channels.php reviewed/3 References
  151. 151. 172 051dd9d8d3d2&v=default&b=&from_search=10 051dd9d8d3d2&v=default&b=&from_search=12 051dd9d8d3d2&v=default&b=&from_search=8 051dd9d8d3d2&v=default&b=&from_search=23 shift-keying-tutorial.php References