3G通讯的发展与应用趋势技术篇

1、3G通訊的發展與應用趨勢技術篇Contents Basic Concept of Mobile SystemDevelopment of Mobile CommunicationGSM Network ArchitectureCDMA Network ArchitectureObjectivesUnderstand the development of 3GName the concept of the three different multiple access technologies and understand where each be usedUnderstand the IMT

2、-2000 systemOn completion of this section will be able to:Year 2000 and LaterBetter Voice ServiceHigh Rate Data AccessMore Value-added ServiceLarge CapacityHigher Spectrum EfficiencyMore Safe ServiceLow Operation CostHigh Quality VoiceHigh Speed Mobile AccessMulti Media, E-CommercePersonalized Servi

3、ceNew Requirement90sBetter Voice ServiceSome Value-added ServiceLarge CapacityLow Operation CostEnhance Spectrum EfficiencyHigh Quality VoiceLower Data ServiceShort MessageCurrent RequirementEarlier Requirement80sVoice ServiceCapacityBasic Voice Service,Voice QualityOperatorCustomerDifferent Period,

4、 Different Requirement Different Requirement, Different Technology 3G provides customers and operators with complete integrated service solutions AMPSTACSNMT其它Generation 1 in the 1980sAnalogAnalog technology (l) GSMCDMA IS95TDMAIS-136PDCGeneration 2 in the 1990sDigitalDigital technology Voice servic

5、e Generation 3IMT-2000UMTSWCDMAcdma2000TD-SCDMABroadband service Multiple Access TechnologiesUser 1User 2User 3TimeFrequencyFDMATimeFrequencyCodeCDMAUser3 User2 User1 Based on codes, all users obtain traffic channels at the same time and on the same frequency band, for example, WCDMA and CDMA2000Tra

6、ffic channels on different frequency bands are allocated to different users,for example, AMPS and TACSTraffic channels at different time slots are allocated to different users, for example, DAMPS and GSMUser 1User 2TimeFrequencyTDMAUser 9User 10Objectives of 3GGlobally universal frequency band and s

7、tandard, global seamless coverage Highly effective spectrum efficiencyHigher quality of service, security and reliabilityEasy to smoothly develop and transit from 2G, compatible with 2G in a reverse directionProviding multimedia services, with the rate of up to 2MbpsVehicle environment: 144kbpsEnvir

8、onment for walk: 384kbpsIndoor environment: 2MbpsIMT-2000 Technical Specification System3GSystemWCDMACore Network：Based on MAP & GPRSRTT： WCDMAFDD/TDD TD-SCDMARTT Specification：TD-SCDMAOther systems:EDGE DECTCDMA2000Network：Based on ANSI 41 & MAPRTT：CDMA2000Comparison of the Three ModesWCDMAcdma2000

9、TD-SCDMAStructure of the receiver RAKERAKERAKEClosed loop Power control SupportedSupportedSupportedHandoffSoft/hard handoff Demodulation modeCoherent demodulation Chip rate (Mcps) 3.84N*1.22881.28Mode of transmit diversityTSTDSTTDFBTDOTDSTSNoMode ofsynchronization AsynchronousSynchronousAsynchronous

10、Core network GSM MAPANSI-41GSM MAPCoherent demodulation Coherent demodulation Soft/hard handoff Soft/hard handoff Contents Basic Concepts of Mobile SystemDevelopment of Mobile CommunicationGSM Network ArchitectureCDMA Network ArchitectureObjectivesOn completion of this section the student will be ab

11、le to: Name the data servicesUnderstand the 3 location servicesData Services032649.61281443842,000Video StreamingVoiceText MessagingStill ImagingAudio StreamingElectronic newspaperHigh-quality videoconferenceTelephone (Voice)Voice MailE-MailFax Electronic bookSports, news and weather report on deman

12、d Singing roomLow-quality videoconferenceJPEG Still PhotosMobile RadioVideo Surveillance,Video Mail, TravelImageDataWeather, transportation, news, sports and securitiesMobile TVE-commerceRemoteMedical ServiceDevelopment orientation of a networkThere are 3 location technology standards: Location Serv

13、icesGPS-aided measurement Accuracy: Suburbs-10m City-3070m Indoorunable to locate Response time: 310sMeasurement of base station pilot phase Accuracy: 50200m Response time: 36sLocating of a cell ID Accuracy: depends on the size of a cell Response time: within 3sVVVROOM !110! Bandit!The system transf

14、ers to the nearest alarm processing center based on the location information of the user reporting an alarm.An alarm button can be set on a users mobile phone to achieve the goal of reporting an alarm without any conversation.Location ServicesContents Basic Concepts of Mobile SystemDevelopment of Mo

15、bile CommunicationGSM Network ArchitectureCDMA Network ArchitectureObjectivesName the frequency spectrum used in GSMName the service areaName the two different cell types and understand why and when each would be used.Name the concept of frequency reuse.Understand the Characteristic of radio communi

16、cationOn completion of this section will be able to:The Division Of Radio FrequencyDifferent frequency has different propagation characteristicsThe Division Of Radio Frequency300-3000GHzEHFExtremely HighFrequency30-300GHzSHFSuper High Frequency3-30GHzUHFUltra High Frequency300-3000MHzVHFVery High Fr

17、equency30-300MHzHFHigh Frequency3-30MHzMFMedium Frequency300-3000KHzLFLow Frequency30-300KHzVLFVery-low Frequency3-30KHzVFVoice Frequency300-3000HzELFExtremely LowFrequency30-300Hz3-30HzDesignationClassificationFrequencyIMT-2000 Frequency Assignment185019001950200020502100215022002250ITUEuropeUSAMSS

18、PCSADBBCDCEFAFEMSSReserveBroadcast auxiliary2165 MHz1990 MHz1850190019502000205021002150220022501880 MHz1980 MHzUMTSGSM 1800DECTMSS1885 MHz2025 MHz2010 MHzIMT 2000MSSUMTSJapanMSSIMT 2000MSSIMT 2000PHS18951918BC1885AA2170 MHzIMT 20002110 MHz2170 MHzMSSMSSCDMATDDWLLFDDWLL19802025MHzGSM1800CDMAFDDWLL19

19、6019201945Chinacellular(1)cellular(2)cellular(2)1805 MHz186518651870188518901895191019301945196519701975The Frequency SpectrumTACS/GSMSeparation 45MHzChannel Bandwidth: 200KHzETACS/EGSM872 890 905 915 917 935 950 960MHzTACS/GSMGSMETACS/ EGSMTACS/GSMGSMThe Frequency SpectrumSeparation: 95MHzChannel B

20、andwidth: 200KHzBase Station Receive1710 1785 1805 1880MHzBase Station TransmitDCS 1800The Frequency SpectrumCDMA450MHz800MHz1900MHz2100MHzSeparation increasesService Area PLMN service area.System area PLMN service areaMSC area.Location area.Base station area.Radio cell.MSC area.Location area.Base s

21、tation area.Radio cellPLMN service areaCELLOmni1120degree123Omni-Directional Cells120 Degree SectorsFrequency Re-Use4(Site)X 3(Cell) Re-use51961027311591102128411739516Illustration of 4*3 Frequency Reuse 1 2 3 4 5 6 7 8 9 10 11 12 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56

22、57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 Forward wave and Earth reflection wave（normal propagation model）Troposphere lay reflection radio wave（propagation with the randomicity）Mountain diffracted wave （signal origin of shado

23、w area）ionosphere reflection radio wave （over sight communication approach）Radio wave broadcast pathDownlink and UplinkDownlink (in GSM)Forward (in CDMA)Uplink (in GSM)Reverse (in CDMA)Power ControlSave battery powerReduce interference8W0.8W5WBoth Uplink and Downlink power settings can be controlled

24、 independently and individually.HandoffKeep voice/data successionIncrease network service qualityLow voice/data dropping rateBetter voice/data qualityTypes of HandoffSoft handoff A multi-sectors handoff, in which the mobile station keeps connecting with the previous base station. Soft handoff enhanc

25、es the voice quality and decreases the possibility of call dropping. Softer handoff Just like the soft handoff, the softer handoff takes place among the multi-sectors in the same base station.Hard handoff In the course of handoff, the mobile station will be disconnected from the previous base statio

26、n before connecting with the next base station. And this kind of handoff is characterized by a temporary disconnection of the traffic channel and includes Frequency change hard handoff Intersystem hard handoffSoft Handoff/Softer HandoffMulti-path combination in the BSC during soft handoffMulti-path

27、combination in the BTS during softer handoffs Combine all the power from each sectorPower received from a single sectorWhen loads of adjacent cells are different, the cell with heavier load lows its transmit rate and users at the edge of the cell hand off to the adjacent cells, so as to implement lo

28、ad control. Cell BreathDynamic cell load allocation by cell breath brings better networkcoverage and larger system capacity.Load control mainly involves cell breath and handoff between cells on different frequencies.Multipath FadingDiversity Time diversityBlock interleaving, error-correcting.Frequen

29、cy diversityIn GSM system, use Frequency Hopping The CDMA signal energy is distributed on the whole 1.23MHZ bandwidth.Space diversityThe introduction of twin receive antennas .The RAKE Receivers of the mobile station and the base station can combine the signals of different time delay.During a hando

30、ff, the mobile station contacts multiple base stations and searches for the strongest frame. Space DiversityWhen diversity is implemented two antennas are situated at the receiver. These antennas are placed several wavelengths apart to ensure minimum correlation between the two receive paths.The two

31、 signals are then combined, this ensures that a low signal strength is less likely to occur.Compare oradd signalsResultant SignalApprox. 10 wavelengthsFrequency HoppingEach time the BTS or mobile transmits a burst, it does so on a different RF carrier frequency.timefrequencyRAKE ReceiverThe RAKE tec

32、hnology can overcome the multi-path fading and enhance the receive performance of the system.Receive setCorrelator 1Correlator 2Correlator 3Searcher correlatorCalculate the time delay and signal strength CombinerThe combined signaltts(t)s(t)VAD & DTXEncoding the speech silences at a rate of 500 bit/s rather than the full 13Kb/s.