Báo cáo WCDMA RAN Fundamental

WCDMA RAN FundamentalObjectivesUpon completion of this course, you will be able to:Know the development of 3GOutline the advantage of CDMA principleCharacterize code sequenceOutline the fundamentals of RANDescribe feature of wireless propagation 2Contents3G OverviewCDMA PrincipleWCDMA Fundamental3Contents3G OverviewCDMA PrincipleWCDMA Fundamental4Different Service, Different TechnologyAMPSTACSNMTOthers1G 1980sAnalog GSMCDMA IS-95TDMAIS-136PDC2G 1990sDigital Technologies drive3G IMT-2000UMTSWCDMAcdma2000Demands driveTD-SCDMA3G provides compositive services for both operators and subscribers 5Different Service, Different TechnologyAMPSTACSNMTOthers1G 1980sAnalog GSMCDMA IS-95TDMAIS-136PDC2G 1990sDigital Technologies drive3G IMT-2000UMTSWCDMAcdma2000Demands driveTD-SCDMA3G provides compositive services for both operators and subscribers 63G EvolutionProposal of 3G IMT-2000: the general name of third generation mobile communication system The third generation mobile communication was first proposed in 1985，and was renamed as IMT-2000 in the year of 1996Commercialization: around the year of 2000Work band : around 2000MHzThe highest service rate :up to 2000Kbps73G Spectrum Allocation8Bands WCDMA UsedMain bands1920 ~ 1980MHz / 2110 ~ 2170MHzSupplementary bands: different country maybe different1850 ~ 1910 MHz / 1930 MHz ~ 1990 MHz (USA)1710 ~ 1785MHz / 1805 ~ 1880MHz (Japan)890 ~ 915MHz / 935 ~ 960MHz (Australia)Frequency channel number＝central frequency×5, for main band: UL frequency channel number ：9612～9888DL frequency channel number : 10562～1083893G Application ServiceTime Delay BERbackgroundconversationalstreaminginteractive10The Core technology of 3G: CDMACDMA WCDMACN: based on MAP and GPRSRTT: WCDMA - FDD/TDD TD-SCDMACN: based on MAP RTT: TD-SCDMA cdma2000CN: based on ANSI 41 and MIPRTT: cdma200011WCDMA Protocol Version Evolution3GPP Rel993GPP Rel4 3GPP Rel5 200020012002GSM/GPRS CNWCDMA RTTIMSHSDPA 3GPP Rel6 MBMSHSUPA2005CS domain change to NGNWCDMA RTT12WCDMA System ArchitectureRNSRNCRNSRNCCore NetworkNode BNode BNode BNode BIu-CSIu-PSIurIubIubIubIubCNUTRANUEUuCSPS13Protocol Mode for UTRAN Terrestrial InterfaceThe structure is based on the principle that the layers and planes are logically independent of each other. Application ProtocolData Stream(s)ALCAP(s)Transport Network LayerPhysical LayerSignalling Bearer(s)Control PlaneUser PlaneTransport Network User PlaneTransport Network Control PlaneRadio Network LayerSignalling Bearer(s)Data Bearer(s)Transport Network User Plane14Contents3G OverviewCDMA PrincipleWCDMA Fundamental15Multiple Access and Duplex TechnologyMultiple Access TechnologyFrequency division multiple access (FDMA)Time division multiple access (TDMA)Code division multiple access (CDMA)16Multiple Access TechnologyfrequencytimepowerFDMAfrequencytimepowerTDMApowertimeCDMAfrequency17Multiple Access and Duplex TechnologyDuplex TechnologyFrequency division duplex (FDD)Time division duplex (TDD)18Duplex TechnologyTimeFrequencyPowerTDDUSER 2USER 1DLULDLDLULFDDTimeFrequencyPowerULDLUSER 2USER 119Contents3G OverviewCDMA PrincipleWCDMA Fundamental20Processing Procedure of WCDMA SystemSourceCodingChannelCodingSpreadingModulationSourceDecodingChannelDecodingDespreadingDemodulationTransmissionReceptionchipmodulated signalbitsymbolServiceSignalRadio ChannelServiceSignalTransmitterReceiver21Process GainProcess GainProcess gain differs for each service. If the service bit rate is greater, the process gain is smaller, UE needs more power for this service, then the coverage of this service will be smaller, vice versa.22WCDMA Source CodingAMR (Adaptive Multi-Rate) SpeechA integrated speech codec with 8 source rates.The AMR bit rates can be controlled by the RAN depending on the system load and quality of the speech connections.Video Phone ServiceH.324 is used for VP Service in CS domain.Includes: video codec, speech codec, data protocols, multiplexing and etc. CODECBit Rate (kbps)AMR_12.2012.2 (GSM EFR)AMR_10.2010.2AMR_7.957.95AMR_7.407.4 (CDMA EFR)AMR_6.706.7 (PDC EFR)AMR_5.905.9AMR_5.155.15AMR_4.754.7523WCDMA Channel CodingEffectEnhance the correlation among symbols so as to recover the signal when interference occursProvides better error correction at receiver, but brings increment of the delayTypesNo CodingConvolutional Coding (1/2, 1/3)Turbo Coding (1/3)Code Block of N BitsNo Coding1/2 Convolutional Coding 1/3 Convolutional Coding 1/3 Turbo Coding Uncoded N bitsCoded 2N+16 bitsCoded 3N+24 bitsCoded 3N+12 bits24WCDMA InterleavingEffectInterleaving is used to reduce the probability of consecutive bits errorLonger interleaving periods have better data protection with more delay0 0 1 0 0 0 0 . . . 1 0 1 1 10 0  0 1 0  1 0 0  1 0  1 1 Inter-column permutation Output bitsInput bits 	Interleaving periods: 10, 20, 40, or 80 ms 25CorrelationCorrelation measures similarity between any two arbitrary signals. Identical and Orthogonal signals:Correlation = 0Orthogonal signals -1 1 -1 1-1 1 -1 11 1 1 1+1-1+1-1+1-1+1-1Correlation = 1Identical signals-1 1 -1 11 1 1 1-1 1 -1 1C1C2+1+1C1C226Orthogonal Code Usage - CodingUE1: 	＋1	－1 UE2:	－1	＋1 C1 :	－1 ＋1 －1 ＋1 －1 ＋1 －1 ＋1C2 :	＋1 ＋1 ＋1 ＋1 ＋1 ＋1 ＋1 ＋1 UE1×c1：	－1 ＋1 －1 ＋1 ＋1 －1 ＋1 －1UE2×c2：	－1 －1 －1 －1 ＋1 ＋1 ＋1 ＋1 UE1×c1＋ UE2×c2：	－2 0 －2 0 ＋2 0 ＋2 027Orthogonal Code Usage - DecodingUE1×C1＋ UE2×C2: 	 	 －2 0 －2 0 ＋2 0 ＋2 0UE1 Dispreading by c1:	 －1 ＋1 －1 ＋1 －1 ＋1 －1 ＋1Dispreading result:	 ＋2 0 ＋2 0 －2 0 －2 0Integral judgment: ＋4 (means＋1) －4 (means－1)UE2 Dispreading by c2:	＋1 ＋1 ＋1 ＋1 ＋1 ＋1 ＋1 ＋1 Dispreading result:	－2 0 －2 0 ＋2 0 ＋2 0Integral judgment: 	－4 (means－1) ＋4 (means＋1)28Spectrum Analysis of Spreading & DispreadingSpreading codeSpreading codeSignal CombinationNarrowband signalfP(f)Broadband signalP(f)fNoise & Other SignalP(f)fNoise+Broadband signalP(f)fRecovered signal P(f)f29Spectrum Analysis of Spreading & DispreadingMax allowed interferenceEb/No RequirementPowerMax interference caused by UEProcessing GainEbitDespreadingInterference from other UEEchipEb / No = Ec / Io ×PG30Spreading TechnologySpreading consists of 2 stepsChannelization operation, which transforms data symbols into chipsScrambling operation is applied to the spreading signalData bitOVSF codeScrambling codeChips after spreading31WCDMA Channelization CodeOVSF Code (Orthogonal Variable Spreading Factor) is used as channelization code SF = 8SF = 1SF = 2SF = 4Cch,1,0 = (1)Cch,2,0 = (1,1)Cch,2,1 = (1, -1)Cch,4,0 = (1,1,1,1)Cch,4,1 = (1,1,-1,-1)Cch,4,2 = (1,-1,1,-1)Cch,4,3 = (1,-1,-1,1)Cch,8,0 = (1,1,1,1,1,1,1,1)Cch,8,1 = (1,1,1,1,-1,-1,-1,-1)Cch,8,2 = (1,1,-1,-1,1,1,-1,-1)Cch,8,3 = (1,1,-1,-1,-1,-1,1,1)Cch,8,4 = (1,-1,1,-1,1,-1,1,-1)Cch,8,5 = (1,-1,1,-1,-1,1,-1,1)Cch,8,6 = (1,-1,-1,1,1,-1,-1,1)Cch,8,7 = (1,-1,-1,1,-1,1,1,-1)32WCDMA Channelization CodeSF = chip rate / symbol rateHigh data rates → low SF codeLow data rates → high SF code Radio bearerSFRadio bearerSFSpeech 4.75 UL128Speech 4.75 DL256Speech 12.2 UL64Speech 12.2 DL128Data 64 kbps UL16Data 64 kbps DL32Data 128 kbps UL8Data 128 kbps DL16Data 144 kbps UL8Data 144 kbps DL16Data 384 kbps UL4Data 384 kbps DL833Purpose of Channelization CodeChannelization code is used to distinguish different physical channels of one transmitterFor downlink, channelization code ( OVSF code ) is used to separate different physical channels of one cellFor uplink, channelization code ( OVSF code ) is used to separate different physical channels of one UE 34Purpose of Scrambling CodeScrambling code is used to distinguish different transmittersFor downlink, Scrambling code is used to separate different cellsFor uplink, scrambling code is used to separate different UE 35Scrambling CodeScrambling code: GOLD sequence.In UMTS, Gold codes were chosen for their very low peak cross-correlation.There are 224 long uplink scrambling codes which are used for scrambling of the uplink DPCCH/DPDCH. Uplink scrambling codes are assigned by higher layers.For downlink physical channels, 8192 scrambling codes are used.36Downlink Scrambling CodeA primary scrambling code and 15 secondary scrambling codes are included in a set.Scrambling codes for downlink physical channelsSet 0Set 1Set 511Primary scrambling code 0Secondary scrambling code 1Secondary scrambling code 15Primary scrambling code 511*16Secondary scrambling code 511*16+158192 scrambling codes512 sets37Primary Scrambling Code GroupPrimary scrambling codes for downlink physical channelsGroup 0Primary scrambling code 0Primary scrambling code 8*63Primary scrambling code 8*63 +7512 primary scrambling codesGroup 1Group 63Primary scrambling code 1Primary scrambling code 864 primary scrambling code groupsEach group consists of 8 primary scrambling codes38Code MultiplexingDownlink Transmission on a Cell LevelScrambling codeChannelization code 1Channelization code 2Channelization code 3User 1 signalUser 2 signalUser 3 signalNodeB39Code MultiplexingUplink Transmission on a Cell LevelNodeBScrambling code 3User 3 signalChannelization codeScrambling code 2User 2 signalChannelization codeScrambling code 1User 1 signalChannelization code40Modulation Overview1001timeBasic steady radio wave:carrier = A.cos(2pFt+f)Amplitude Shift Keying:A.cos(2pFt+f)Frequency Shift Keying:A.cos(2pFt+f)Phase Shift Keying:A.cos(2pFt+f)Data to be transmitted:Digital Input41Modulation OverviewDigital Modulation - BPSK1t1101t-1NRZ codingfoBPSKModulatedBPSK signalCarrierInformation signal =0 = =01102349875611023498756Digital InputHigh FrequencyCarrierBPSK Waveform42Modulation OverviewDigital Modulation - QPSK-1 -11102349875611023498756NRZ InputI di-Bit StreamQ di-Bit StreamIComponentQComponentQPSK Waveform11-11-111-1-1-11 1-1 1-1 11 -143Modulation OverviewNRZ coding90oNRZ codingQPSKQ(t)I(t)fo±A±A±Acos(ot)±Acos(ot + /2) 	  1	1	/4 1	-1	7/4 -1 1	3/4 -1	-1	5/444DemodulationQPSK Constellation Diagram11023498756QPSK Waveform1,1-1,-1-1,11,-11-11-11-1-11-11-1,1NRZ Output45WCDMA ModulationDifferent modulation methods corresponding to different transmitting abilities in air interfaceHSDPA: adopt 16QAMR99/R4: adopt QPSK46Wireless PropagationReceivedSignalTransmittedSignalTransmission Loss:Path Loss + Multi-path FadingTimeAmplitude47Propagation of Radio SignalSignal at TransmitterSignal at Receiver-40-35-30-25-20-15-10-5dB00dBm-20-15-10-55101520Fading48Fading CategoriesFading CategoriesSlow FadingFast Fading49Diversity TechniqueDiversity technique is used to obtain uncorrelated signals for combiningReduce the effects of fadingFast fading caused by multi-pathSlow fading caused by shadowingImprove the reliability of communicationIncrease the coverage and capacity50DiversityTime diversityChannel coding, Block interleavingFrequency diversityThe user signal is distributed on the whole bandwidth frequency spectrumSpace diversityReceive space diversity Transmit space diversityPolarization diversityVertical polarizationHorizontal polarization51Principle of RAKE ReceiverReceive setCorrelator 1Correlator 2Correlator 3Searcher correlatorCalculate the time delay and signal strength CombinerThe combined signaltts(t)s(t)RAKE receiver help to overcome on the multi-path fading and enhance the receive performance of the system52SummaryIn this course, we have discussed basic concepts of WCDMA:Spreading / Despreading principleUTRAN Voice CodingUTRAN Channel CodingUTRAN Spreading CodeUTRAN Scrambling CodeUTRAN ModulationUTRAN Transmission/Receiving53