Simulation of Third Generation CDMA Systems - Virginia Tech

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Let n 23 ……..n 0 be the 24 bit binary representation of the scrambling code number n(decimal). In the binary representation, n 0 is the least significant bit (LSB). The x sequencedepends on the choice of the scrambling code number and is thus denoted as x n . Furthermore,let x n (i) and y(i) denote the i thsymbol of the sequences x n and y respectively. The msequences are constructed asThe Initial conditions are set:x ( 0) = n , x ( 1) = n ,......, x ( 22) = n , x ( 23) = n , x ( 24)= 1n 0 n 1 n 22 n 23 ny( 0) = y( 1) = ...... y( 23) = y( 24)= 1(2.7)Then subsequent symbols are generated recursively according to:25x ( i+ 25) = x ( i+ 3) + x ( i) , i = 0, 1,......2 -27n n nmod 225yi ( + 25) = yi ( + 3) + yi ( + 2) + yi ( + 1) + yi ( ) , i= 0, 1,......2 -27mod 2(2.8)The real chip rate code C 1,n and C 2,n for the nth scrambling code are defined asC = x ( 0) + y( 0) , x ( 1) + y( 1) ,...., x ( N - 1) + y( N -1)C1, n n mod 2 n mod 2 nmod 22,n== B% xn( M)xn( M + 1)xn( M + N -1)&K(,,...,'K)K+ y( M)+ y( M + 1)+ y( M + N -1)mod 2 mod 2 mod 2*K(2.9)The scrambling codes are designed so that they have very low cross-correlationamong them. This ensures good Multiple Access Interference (MAI) rejection capability.Figure shows a histogram of cross-correlation values for two long scrambling codes.20
0.180.160.140.12Probabilty Density0.10.080.060.040.0200 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05Correlation ValueFigure 2.9: Histogram of Cross-correlation of Long Scrambling Codes2.5.2 Uplink Short Scrambling Codes276543210c tmod 2276543210b smod 4z vMappermod 276543210a r3323mod 4Figure 2.10: Uplink Short Scrambling Code GeneratorThe short scrambling codes are generated in the same way as described in section 2.5.Here the real and imaginary parts of the complex spreading codes, C 1 and C 2 respectively, aretaken from a family of periodically extended S(2) codes. The uplink short codes S v (n),21
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 and 20: Chapter 2WCDMA Physical LayerThis c
Page 21 and 22: Channelization Code(C D )cos(ω c t
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: The following block diagram shows t
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
Page 71 and 72: 10 0 Number of Interfererssf=32sf=1
Page 73 and 74: 10 0 E b/N 00 interferer2 interfere
Page 75 and 76: 10 -1 Number of InterferersBER10 -2
Page 77 and 78: constraint length. So for a constra
Page 79 and 80: Table 4.1: Performance Improvement
Page 81 and 82:
channel model based on measurement
Page 83 and 84:
[7] Kevin Laird, Nick Whinnet, and
Page 85:
VitaFakhrul Alam was born in Dhaka,
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Simulation of Third Generation CDMA Systems - Virginia Tech

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