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WCDMA3G_TCDecoder_Base


Description: Turbo code sub-decoder
Library: 3GPPFDD 10-99, Channel Coding
Class: SDFWCDMA3G_TCDecoder_Base

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

in

input encoded code block

real

2

Priori

priori probability

real

3

CurSize

size of current input block

int

Pin Outputs

Pin

Name

Description

Signal Type

4

out

output decision

int

5

Post

log a posterior probability

real

Notes/Equations
  1. This subnetwork model is used to implement one-step turbo code MAP decoding iteration process.
    The schematic for this subnetwork is shown in the following figure.

    WCDMA3G_TCDecoder_Base Schematic
  2. Coding schemes are listed in the following table.
    Input bits stream are decoded to block sizes according to TrCHType and TTI (which is compliant with [1]).

    DCHType

    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 tokens are produced continuously at out, BlockSize + 3 tokens are produced at post when BlockSize × 3 + 12 in, BlockSize + 3 Priori, and one CurSize tokens are consumed. The following table lists BlockSize values.
    BlockSize Values
    Downlink/Uplink Data Source 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. 3GPP Technical Specification TS 25.212 V3.0.0 "Multiplexing and Channel Coding (FDD)," October 1999.
  2. 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.
  3. 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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