Simulation of Third Generation CDMA Systems - Virginia Tech

More documents

Recommendations

Info

2.3 Downlink Frame StructureFigure 2.4 shows the principal frame structure of the downlink dedicated physicalchannels. As in the uplink, each frame of 10 ms is split into 15 slots. Each slot is of length2560 chips, corresponding to one power control period. A super frame corresponds to 720ms, i.e. the super frame length corresponds to 72 frames.TFCI Data 1 TPC Data 2 PilotT slot =2560 chips, 10×2 k bits (k = 0..7)Slot 1 Slot i Slot 15T f =10 msFrame 1 Frame i Frame 72T super =720 msFigure 2.4: Frame Structure for Downlink DPCHThe parameter k is related to the SF of the physical channel asSF= 512k2(2.2)The spreading factor thus has a range of 4 to 512. Thus an additional spreading factorof 512 is permitted at the downlink. The different control bits have similar meaning to thosein the uplink. The exact number of bits in each of the downlink DPCH fields is described in[6].14
2.4 Uplink Spreading CodesThe spreading code, as the name suggests, spreads the data to the chip rate of 3.84mega chips per second (Mcps). The most important purpose of the spreading codes is to helppreserve orthogonality among different physical channels of the uplink user. As mentioned insection 2.1.1, OVSF codes are employed as uplink spreading codes. OVSF codes can beexplained using the code tree shown in the next figure. The subscript here gives the spreadingfactor and the argument within the parenthesis provides the code number for that particularspreading factor.c 4 (1)= (1,1,1,1)c 2 (1)=(1,1)c 4 (2)= (1,1,-1,-1)c 1 (1)= (1)c 2 (2)= (1,-1)c 4 (3)= (1,-1,1,-1)c 4 (4)= (1,-1,-1,1)SF = 1 SF = 2SF = 4Figure 2.5: Code-tree for Generation of OVSF CodesEach level in the code tree defines spreading codes of length SF, corresponding to aparticular spreading factor of SF. The number of codes for a particular spreading factor isequal to the spreading factor itself. All the codes of the same level constitute a set and theyare orthogonal to each other. Any two codes of different levels are orthogonal to each otheras long as one of them is not the mother of the other code [8]. For example the codesc 16 (2),c 8 (1) and c 4 (1) are all mother codes of c 32 (3) and hence are not orthogonal to c 32 (32).Thus all the codes within the code tree can not be used simultaneously by a mobile station. A15
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: DataPilotTFCI FBI TPCT slot =2560 c
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
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,
show all

Simulation of Third Generation CDMA Systems - Virginia Tech

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?