讲义分析培训cdma physical layer training

1、CDMA Physical Layer TrainingXu Taylor Jan. 2004Beijing, ChinaAgendaConcept of CDMASpread SpectrumCDMA Protocol Architecture OverviewForward Link Channel StructureReverse Link Channel StructureConcept of CDMAThe problem we have to face is that resource is limit. Example: Supposed that China CDMA team

2、 have several groups, but only one big conference room available for different group meetings. How to arrange it ?Method one: Separate the big conference room to several small room for each group.Method two: Each group uses big conference room at different time.Method three: All groups use the same

3、big conference room at the same time. But each group use different languages.Concept of CDMAFDMA - Frequency Division Multiple AccessAMPSTACSFrequencyPowerTimeConcept of CDMATDMA - Time Division Multiple AccessGSMFrequencyTimePowerConcept of CDMACDMA - Code Division Multiple AccessFrequencyTimeCodeS

4、pread SpectrumDirect Spread SpectrumData bits1 0 0Spreading1 0 1 1 0 0 1 1 1 0 1 1 0 0 1 1 1 0 1 1 0 0 1 1CodeXORChips0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 1 0 1 1 0 0 1 19.6 kHz Voice Data1.2288 MHz9.6 kHz Voice DataSpreadDe-spreadSpread SpectrumSpread Rate The PN chip rate of the system, defined as a mu

5、ltiple of 1.2288 Mcps.Spreading Rate 1 1.2288 Mcps chip rate-based system using a direct-spread single carrierSpreading Rate 3 3.6864 Mcps chip rate-based system using three 1.2288 Mcps carriers or a single 3.6864 Mcps direct-spread carrier on the Forward CDMA Channel. The Reverse CDMA Channel uses

6、a 3.6864 Mcps direct-spread carrier. Spread SpectrumSpreading FactorSpreading Factor=W(Bandwidth in Hz)R(Data rate in bits/second)For 9.6 kHz voice data spread to 1.2288MHz, spreading Factor is Spreading Factor=12288009600=128CDMA Protocol Architecture OverviewIS-2000-2 : Physical Layer Standard for

7、 cdma2000 Spread Spectrum SystemsIS-2000-3 : Medium Access Control (MAC) Layer Standards for cdma2000 Spread Spectrum SystemsIS-2000-4 : Signaling Link Access Control (LAC) Layer Standard for cdma2000 Spread Spectrum SystemsIS-2000-5 : Upper Layer (L3) Signaling Standard for cdma2000 Spread Spectrum

8、 SystemsLayer1 Physical LayerLayer2 LAC&MACLayer 3 SignalingCDMA Protocol Architecture OverviewLayer 1 - Physical LayerThe physical layer in the transmitting station is presented a frame and transforms it into an over-the-air waveform. The physical layer in the receiving station transforms the wavef

9、orm back into a frame.CDMA Protocol Architecture OverviewLayer 2 LAC&MACLayer 2 provides for delivery of signaling messages generated by Layer 3 . Layer 2 consists of two sub-layers: the LAC Sub-layer and the MAC Sub-layer. MAC sub-layer is the lower sub-layer of Layer 2. It implements the medium ac

10、cess protocol and is responsible for transport of LAC protocol data units using the services provided by Layer 1. The LAC Sub-layer is the upper sub-layer of Layer 2. It implements a data link protocol that provides for the correct transport and delivery of signaling messages generated by Layer 3. C

11、DMA Protocol Architecture OverviewLayer 3 Signaling Layer 3 originates and terminates signaling messages according to the semantics and timing of the communication protocol between the base station and the mobile station. Layer 3 makes use of the services provided by Layer 2. Forward Link Channel St

12、ructureChannel Types on CDMA forward link for spreading rate 1Forward Link Channel StructureForward Link Channel StructureNetwork and Phone NOT supported channels by nowBroadcast Control Channel (BCCH) Common Control Channel (CCCH)Dedicated Control Channel (DCCH)Channel Assignment Channel (CACH)Comm

13、on Power Control Channel (PCCH)Forward link Auxiliary Pilot ChannelForward link Transmit Diversity (OTD & STS)Forward link Transmit Diversity Pilot ChannelForward link Auxiliary Transmit Diversity Pilot ChannelForward Link Channel StructureConvolutionEncodingSymbolRepetitionBlockInterleavingOrthogon

14、alSpreadingLong CodeMasking&PCB PuncturingQPSKModulationForward Link Block DiagramForward Link Channel StructureFQITailBits1/2 rateEncoderSymbolRepeatPuncture(RS2)BlockInterleave+Long CodeGeneratorDecimatorDecimatorDataWalsh NPowerControl BitsLong CodeMask+AI PNBasebandFilterBasebandFilterCos1/2 rat

15、eEncoderSymbolRepeatBlockInterleave+Long CodeGeneratorDecimatorWalsh (paging)ALong CodeMaskPagingData1/2 rateEncoderSymbolRepeatBlockInterleave+Walsh 32ASyncData+Walsh 0A0S(t)PilotSinQ PNReverse Link Channel StructureChannel Types on the Reverse CDMA Channel for Spreading Rate 1Reverse Link Channel StructureNetwork and Phone NOT supported cha