3rd Generation SystemsCellular Wireless Network EvolutionCellular Evolution (cont)Cellular ConceptAMPS (Advanced Mobile Phone System): FDMAHandoffDigital Cellular: IS-54 TDMA SystemIS-54 slot and frame structureGSM (Group Special Mobile)GSM functions - TDMA access techniqueSlide 11UMTS (Universal Mobile Transport Service)Third generation servicesUTRAN (UMTS Terrestrial Radio Access Net) ArchitectureSlide 16W-CDMA (Wide Band CDMA)Radio Interface - protocol architectureLayer 1 - up link physical channels (W-CDMA)Layer 1 - down link physical channels (W-CDMA example)Transport channels (example)Multiplexing transport channels onto physical channelsMS physical layer up-down link example of multiplexingMAC Services and FunctionsRetransmission Protocol - services and functionsRadio Resource control - functionsSlide 27Slide 28Slide 29Slide 30Slide 31Packet Data ServicePacket Data Service (cont)Slide 34Slide 35Real time servicesCongestion ControlHandover modesMacrodiversity - active setThe macrodiversity control3rd Generation Systems•Review of Cellular Wireless Networks•UMTSCellular Wireless Network Evolution•First Generation: Analog–AMPS: Advance Mobile Phone Systems–Residential cordless phones•Second Generation: Digital–IS-54: North American Standard - TDMA–IS-95: CDMA (Qualcomm)–GSM: Pan-European Digital Cellular–DECT: Digital European Cordless TelephoneCellular Evolution (cont)•Third Generation: T/CDMA–combines the functions of: cellular, cordless, wireless LANs, paging etc.–supports multimedia services (data, voice, video, image)–a progression of integrated, high performance systems:(a) GPRS(b) EDGE (c) UMTSCellular Concept•Geographical separation•Capacity (frequency) reuse•Backbone connectivityBSBSBSBSBSBSBackbone NetworkAMPS (Advanced Mobile Phone System): FDMAIn each cell, 57 channels each for A-side carrier and B -side carrierChannels are divided into 4 categories:1. Control (base to mobile) to manage the system.2. Paging (base to mobile) to alert mobile users to incoming calls.3. Access (bidirectional) for call set up and channel assignment.4. Data (bidirectional) for voice, FAX, or dataBAEDCFGBAEDCFGBAEDCFGFrequencies are not reused in adjacent cellsHandoff•Handoff: Transfer of a mobile from one cell to another•Each base station constantly monitors the received power from each mobile.•When power drops below given threshold, base station asks neighbor station (with stronger received power) to pick up the mobile, on a new channel.•The handoff process takes about 300 msec.Digital Cellular: IS-54 TDMA System•Second generation: digital•Same frequency as AMPS•Each 30 kHz RF channel is used at a rate of 48.6 kbps–3 TDM slots/RF band–8 kbps voice coding–16.2 kbps TDM digital channel•4 cell frequency reuse•Capacity increase per cell per carrier–3 x 416 / 4 = 312 (instead of 57 in AMPS)–Additional factor of two with speech activity detection.IS-54 slot and frame structure BASE TO MOBILESLOT 1SLOT 2SLOT 3 SLOT 4 SLOT 5SLOT 6Frame1944 bits in 40 ms( 48600 b/s)G6R6DATA16SYNC28DATA122SACCH12DVCC 12DATA122MOBILE TO BASEDATA130DATA130DVCC 12SACCH 12SYNC28RSVD 12G:GUARD TIME R:RAMP TIMEDVCC: DIGITAL VERIFFICATION COLOR CODERSVD: RESERVE FOR FUTURE USEGSM (Group Special Mobile)Pan European Cellular StandardSecond Generation: DigitalFrequency Division duplex (890-915 MHz Upstream; 935-960 MHz Downstream)125 frequency carriersCarrier spacing: 200 Khz8 channels per carrier (Narrowband Time Division)Speech coder: linear predictive coding (Source rate = 13 Kbps)Modulation: phase shift keying (Gaussian minimum shift keying)Multilevel, time division frame structureSlow frequency hopping to overcome multipath fadingBURSTTRANSMITTEDBYTDMA FRAME(4.6 ms)MOBILE 1MOBILE 2MOBILE 8TIMETIME-SLOT: 577 sSIGNAL BURST: 546 sGSM functions - TDMA access techniqueBCCH: Broadcast Control Channel point-to-multipoint unidirectional control channel broadcasting system information to MSCCCH: Common Control Channelup-link: RACH (Random Access CHannel)down-link: PCH (Paging Channel) AGCH (Access Grant CHannel)DCCH: Dedicated Control CHannel point-to-point bidirectional control channelSACCH (Slow Associated Control CHannel)FACCH (Fast Associated Control CHannel)SDCCH (Stand Alone Dedicated Control CHannel)GSM network architecture and functionsSignalling channelsUMTS (Universal Mobile Transport Service)Requirements•384 Kbps for full area coverage•2 Mbps for local area coverage•variable bit rate•packet traffic support•flexibility (eg, multiple, multimedia streams on a single connection)Third generation services2M384K64K32K16K9.6K2.4K1.2Kpoint to point multipointbidirectional unidirectional multicastvideoconferencevideoconferenceremote medicalservice videocatalogueshoppingvideoondemandmobileTVinternettelephoneconferencetelephonevoice mailelectronicnewspaperISDNelectronicpublishingFAXdistributionservices(data)mobile radiodistributionservices (voice)pagerUTRAN (UMTS Terrestrial Radio Access Net) ArchitectureCore NetworkRNC RNCSite ContrBTS BTS BTSSite ContrBTS BTS BTSSite ContrBTS BTS BTSSite ContrBTS BTS BTSRNSUTRANRNSIubIubIubIubIurIuIuB-node B-nodeB-node B-nodeAccess techniques for mobile communicationsP - PowerT - TimeF - FrequencyPTPTFPTFFDMA (TACS)TDMA (GSM, DECT)CDMA (UMTS)FATDMA (UMTS)W-CDMA (Wide Band CDMA)Key features•Improved capacity and coverage (over second generation CDMA); backward compatible•High degree of service flexibility: multiple, parallel services per connection; efficient pkt access•Operator flexibility: asynchronous interstation operation; hierarchical cell structures (HCS); adaptive antenna arrays (enabled by uplink pilot symbols); TDD (Time Division Duplex) mode for asymmetric traffic and uncoordinated environments.RLCRLCLACLACRadio Interface - protocol architectureRLCRRCLACMACPhysical LayerL3L2/LACL2/MACL1C-planeU-planeLogicalchannelsTransportchannelsRLCLayer 1 - up link physical channels(W-CDMA)DataPilotDedicated PhysicalData Channel Dedicated PhysicalControl ChannelTransmitpower controlTransportformat ind.Slot#1Slot#2 Slot#iSlot#15Frame#1Frame#2 Frame#iFrame#720.667 ms10 msFeedbackindicatorLayer 1 - down link physical channels(W-CDMA example)DataSlot#1Slot#2 Slot#iSlot#15Frame#1Frame#2 Frame#iFrame#72PilotTPCTFIDPCCHDPDCHframesuperframe0.667 ms10 msTransport channels (example)• Dedicated Channel (DCH): fast change of bit rate (10ms)fast power controlinherent MS addressing• Random Access
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