Simulation of Third Generation CDMA Systems - Virginia Tech

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• Primary and secondary Common Control Physical Channels (CCPCH) tocarry downlink common channels• Synchronization Channels (SCH) for cell search• Physical Random Access Channel (PRACH)The spreading and modulation for the DPDCH and the DPCCH for both the links aredescribed in the following two subsections.2.1.1 Uplink Spreading and ModulationIn the uplink the data modulation of both the DPDCH and the DPCCH is BinaryPhase Shift Keying (BPSK). The modulated DPCCH is mapped to the Q-channel, while thefirst DPDCH is mapped to the I-channel. Subsequently added DPDCHs are mappedalternatively to the I or the Q-channel. Spreading Modulation is applied after data modulationand before pulse shaping. The spreading modulation used in the uplink is dual channelQPSK. Spreading modulation consists of two different operations. The first one is spreadingwhere each data symbol is spread to a number of chips given by the spreading factor. Thisincreases the bandwidth of the signal. The second operation is scrambling where a complexvalued scrambling code is applied to spread signal. Figure 2.1 shows the spreading andmodulation for an uplink user. The uplink user has a DPDCH and a DPCCH.The bipolar data symbols on I and Q branches are independently multiplied bydifferent channelization codes. The channelization codes are known as Orthogonal VariableSpreading Factor (OVSF) codes. OVSF codes are discussed in section 2.4.10
Channelization Code(C D )cos(ω c t)Data (DPDCH)Scrambling Code(C SC )p(t)Control (DPCCH)jp(t)Channelization Code(C C )sin(ω c t)Figure 2.1: Uplink Spreading and ModulationThe resultant signal is multiplied by a complex scrambling code. The complexscrambling code is a unique signature of the mobile station. Next, the scrambled signal ispulse shaped. Square-Root Raised Cosine filters with roll-off factor of 0.22 are employed forpulse shaping. The pulse shaped signal is subsequently upconverted as shown in Figure 2.1.The application of a complex scrambling code with spreading modulation asdescribed above is usually termed as Hybrid Phase Shift Keying (HPSK). HPSK reduces thepeak-to-average power of the mobile station by generating the complex scrambling sequencein a special way [7]. The generation of complex scrambling code is discussed in section 2.5.The spreading factor for the control channel is always set at the highest value whichis 256. This improves the noise immunity at the control channel by taking advantage of thehighest possible processing gain.2.1.2 Downlink Spreading and ModulationQuaternary Phase Shift Keying (QPSK) is applied for data modulation in thedownlink. Each pair of two bits are serial-to-parallel converted and mapped to the I and Qbranches respectively. The data in the I and Q branches are spread to the chip rate by thesame channelization code. The channelization code is the same OVSF codes mentioned insection 2.1.1. This spread signal is then scrambled by a cell specific scrambling code. Figure11
Page 1 and 2: Simulation of Third Generation CDMA
Page 3 and 4: AcknowledgmentsI would like to expr
Page 5 and 6: 2.9.2. Transmit Diversity Schemes2.
Page 7 and 8: List of Tables1.1 3G Data Rate Requ
Page 9 and 10: 3.9 Implementation of Pulse shaping
Page 11 and 12: Chapter 1IntroductionThe goal for t
Page 13 and 14: 1.3 Third Generation Cellular Syste
Page 15 and 16: 1.4. WCDMA: Air Interface for 3GOne
Page 17 and 18: 1.4.2 WCDMA Key Technical Character
Page 19: Chapter 2WCDMA Physical LayerThis c
Page 23 and 24: DataPilotTFCI FBI TPCT slot =2560 c
Page 25 and 26: 2.4 Uplink Spreading CodesThe sprea
Page 27 and 28: Figure 2.6: Auto-correlation for Tw
Page 29 and 30: The following block diagram shows t
Page 31 and 32: 0.180.160.140.12Probabilty Density0
Page 33 and 34: ar( 0) = 2vr( 0) + 1 (2.12)mod 4ar(
Page 35 and 36: 2.8 Channel CodingThe main purpose
Page 37 and 38: 2.9.2 Transmit Diversity SchemesTra
Page 39 and 40: These differences will become evide
Page 41 and 42: Dtoffset = 2 (3.15)cHere c is the v
Page 43 and 44: Each ray is split into two rays, on
Page 45 and 46: The pass-band of the pulse shaping
Page 47 and 48: The Rayleigh waveform is generated
Page 49 and 50: This expression can be used directl
Page 51 and 52: e -jϕ1FrameAlignmentResamplingDesc
Page 53 and 54: 3.2.7 BER CounterThe bit error rate
Page 55 and 56: (t)R i ’(t)R i (t)e -jϕ i C SC *
Page 57 and 58: IT+ τT + τi i i I iτ iτ iiiz =
Page 59 and 60: 3.3.2 MAI for DownlinkThe MAI in th
Page 61 and 62: menu is provided which gives the op
Page 63 and 64: up_sim.mpar_up.mat ovsf_gen.m scram
Page 65 and 66: 3.6 Code OptimizationThe simulator
Page 67 and 68: Chapter 4Simulation ResultsThis cha
Page 69 and 70: 10 0 E b/N 010 -1BER10 -210 -30 int
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10 0 Number of Interfererssf=32sf=1
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10 0 E b/N 00 interferer2 interfere
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10 -1 Number of InterferersBER10 -2
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constraint length. So for a constra
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Table 4.1: Performance Improvement
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channel model based on measurement
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[7] Kevin Laird, Nick Whinnet, and
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VitaFakhrul Alam was born in Dhaka,
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