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WCDMA3G_Despreader


Description: De-spread chip sequence of code channels
Library: 3GPPFDD 10-99, Rake Receiver
Class: SDFWCDMA3G_Despreader
Derived From: WCDMA3G_RakeBase

Parameters
Name Description Default Sym Type Range
ChipRate chip rate of system: Chip Rate 3.84Mcps Chip Rate 3.84Mcps   enum  
LinkDir link direction: Downlink, Uplink Downlink   enum  
PilotType basic pilot type: Multiplex Pilot, Downlink Common Pilot Multiplex Pilot   enum  
DL_DPCHType downlink dedicated physical channel: DPCH_15kbps_TF0_T2_P4, DPCH_15kbps_TF2_T2_P4, DPCH_30kbps_TF0_T2_P2, DPCH_30kbps_TF2_T2_P2, DPCH_30kbps_TF0_T2_P4, DPCH_30kbps_TF2_T2_P4, DPCH_30kbps_TF0_T2_P8, DPCH_30kbps_TF2_T2_P8, DPCH_60kbps_TF0_T2_P4, DPCH_60kbps_TF2_T2_P4, DPCH_60kbps_TF0_T2_P8, DPCH_60kbps_TF2_T2_P8, DPCH_120kbps_TF8_T4_P8, DPCH_120kbps_TF0_T4_P8, DPCH_240kbps_TF8_T4_P8, DPCH_240kbps_TF0_T4_P8, DPCH_480kbps_TF8_T8_P16, DPCH_480kbps_TF0_T8_P16, DPCH_960kbps_TF8_T8_P16, DPCH_960kbps_TF0_T8_P16, DPCH_1920kbps_TF8_T8_P16, DPCH_1920kbps_TF0_T8_P16, PCCPCH DPCH_30kbps_TF2_T2_P8   enum  
UL_DPDCHType uplink dedicated physical data channel: DPDCH_15kbps, DPDCH_30kbps, DPDCH_60kbps, DPDCH_120kbps, DPDCH_240kbps, DPDCH_480kbps, DPDCH_960kbps DPDCH_30kbps   enum  
UL_DPCCHType uplink dedicated physical control channel: DPCCH_15kbps_P6_TF2_F0_T2, DPCCH_15kbps_P8_TF0_F0_T2, DPCCH_15kbps_P5_TF2_F1_T2, DPCCH_15kbps_P7_TF0_F1_T2, DPCCH_15kbps_P6_TF0_F2_T2, DPCCH_15kbps_P5_TF2_F2_T1 DPCCH_15kbps_P6_TF2_F0_T2   enum †
PathNum number of paths or fingers of Rake 6 L int [1, 16]
DPCHNum number of DPCHs 1 M int [1, 16]
† where
TFn = number of transmit format indicator bits
Tn = number of transmit power control bits
Pn = number of pilot bits
Fn = number of feedback indicator bits

Pin Inputs

Pin

Name

Description

Signal Type

1

ChpSeq

chip sequences of optimum multi-path

multiple complex

2

SprdCd

bit-wise product of spreading and scrambling codes for DPCHs
or CPICH

multiple complex

Pin Outputs

Pin

Name

Description

Signal Type

3

Symbol

de-spread signals of all code channels of current slot

multiple complex

4

SymCH1

de-spread signals of the first code channel of current slot in downlink,Common
Pilot Channel in downlink or DPCCH in uplink

multiple complex

Notes/Equations
  1. This model is used to despread the resolved multiple path signals from WCDMA3G_DownSample.
    Each firing, N tokens are consumed at ChpSeq and SprdCd, where N is the number of chips per slot. The number of ChpSeq depends on PathNum. Refer to the following table for SprdCd and Symbol and SymCH1 values.
    The complex format of input at SprdCd is Cspread × (Cscramble,i + j × Cscramble,q ). One slot delay is inserted at SprdCd to synchronize ChpSeq.
    SprdCd, Symbol, and SymCH1 Values
    LinkDir PilotType SprdCd Symbol SymCH1
    Downlink Multiplexed Pilot M M × Kd Kd
    Downlink Downlink Common Pilot M+1 M × Kd 10
    Uplink Multiplexed Pilot M M × Ku Ku
    Kd = symbol number in one slot of downlink DPCH
    Ku = symbol number in one slot of uplink DPDCH

References
  1. 3GPP Technical Specification TS25.211 V3.0.0, "Physical channels and mapping of transport channels onto physical channels (FDD)," October 1999.
  2. 3GPP Technical Specification TS25.213 V3.0.0, "Spreading and modulation (FDD)," October 1999.
  3. A. J. Viterbi, "CDMA: Principles of Spread Spectrum Communication," Wesley Publishing Company, 1995.
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