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WCDMA3G_TC_MAPDecoder2


Description: Second MAP sub-decoder
Library: 3GPPFDD 10-99, Channel Coding
Class: SDFWCDMA3G_TC_MAPDecoder2

Parameters

Name

Description

Default

Type

LinkDir

link direction: Downlink, Uplink

Downlink

enum

TrCHType

transport channel type: DCH_8_kbps, DCH_16_kbps, DCH_32_kbps, DCH_64_kbps, DCH_128_kbps, DCH_256_kbps, DCH_512_kbps, DMCH_2_4_kbps, DMCH_12_2_kbps, DMCH_64_kbps, DMCH_144_kbps, DMCH_384_kbps, DMCH_2048_kbps, BCH_11_1_kbps, BCH_12_3_kbps

DCH_64_kbps

enum

TTI

transmission time interval: TTI_10ms, TTI_20ms, TTI_40ms, TTI_80ms

TTI_10ms

enum

TurboCodeType

turbo code type: k 4 g1 013 g2 015 Rate One Third

k 4 g1 013 g2 015 Rate One Third

enum

Pin Inputs

Pin

Name

Description

Signal Type

1

inY

parity bits

real

2

inZ

priori probability bits

real

3

CurSize

size of current input block

int

Pin Outputs

Pin

Name

Description

Signal Type

4

post

log a posterior probability

real

5

pri

priori probability to sub-decoder1

real

Notes/Equations
  1. This model is used to perform maximum a posteriori (MAP) decoding.
    The outputs of the first decoder are interleaved before being sent to this second decoder; tail bits are also sent but cannot be interleaved, so the tail bits are punctured before this interleaver and then padded.
    The second decoder generates the extrinsic information to provide a priori for the first decoder. Outputs are de-interleaved before being sent to decoder 1, tail bits are punctured before de-interleaving and padded afterward.
    The following table lists coding schemes.
    Turbo Coding Schemes

    TrCHType

    LinkDir

    CodeType

    Coding

    DCH_8_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    zero output

    DCH_16_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    zero output

    DCH_32_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    zero output

    DCH_64_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DCH_128_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DCH_256_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DCH_512_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DMCH_2_4_kpbs

    any

    k 4 g1 013 g2 015 Rate One Third

    zero output

    DMCH_12_2_kpbs

    any

    k 4 g1 013 g2 015 Rate One Third

    zero output

    DMCH_64_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DMCH_144_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DMCH_384_kbps

    any

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    DMCH_2048_kbps

    Uplink

    k 4 g1 013 g2 015 Rate One Third

    rate 1/3 coding

    BCH_11_1_kbps

    Downlink

    k 4 g1 013 g2 015 Rate One Third

    zero output

    BCH_12_3_kbps

    Downlink

    k 4 g1 013 g2 015 Rate One Third

    zero output


    Each firing, BlockSize + 3 tokens are produced per BlockSize + 3 input tokens from inY and inZ. One CurSize token is consumed. Refer to the following table for the value of BlockSize. The length of tail bits is 3.
    BlockSize Values
    TrCHType (Downlink or Uplink) BlockSize
    TTI_10 ms TTI_20 ms TTI_40 ms TTI_80 ms
    DCH_64kbps 656 1296 2576 2568
    DCH_128kbps 1296 2576 2576 3419
    DCH_256kbps 2576 2576 3419 4100
    DCH_512kbps 2576 3419 4100 4553
    DMCH_64_kbps   1296    
    DMCH_144_kbps   2896    
    DMCH_384_kbps   3848    
    DMCH_2048_kbps (uplink only)   4553    

References
  1. L.R. Bahl, J. Cocke, F. Jeinek and J. Raviv. "Optimal decoding of linear codes for minimizing symbol error rate." IEEE Trans. Inform. Theory, vol. IT-20. pp.248-287, March 1974.
  2. C.Berrou, A.Glavieux, and P. Thitiumjshima, "Near Shannon limit error correcting coding: Turbo codes," IEEE International Conference on Communications, pp. 1064-1070, May 1993.
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