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WCDMA3G_CRCDecoder


Description: CRC check of transport block
Library: 3GPPFDD 10-99, Channel Coding
Class: SDFWCDMA3G_CRCDecoder

Parameters

Name

Description

Default

Type

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_8_kbps

enum

TTI

transmission time interval: TTI_10ms, TTI_20ms, TTI_40ms, TTI_80ms

TTI_10ms

enum

CRC

number of CRC bits to be added: NoCRC, CRC_8_bits, CRC_12_bits, CRC_16_bits, CRC_24_bits

CRC_16_bits

enum

Pin Inputs

Pin

Name

Description

Signal Type

1

DataIn

transport block with CRC bits attached in tail

int

2

TF

transport format

int

Pin Outputs

Pin

Name

Description

Signal Type

3

DataOut

transport block after removing the CRC bits

int

4

CRCError

CRC checking error indicator

int

Notes/Equations
  1. The model is used to perform CRC checking of a block of transport channel data. The signal processing procedure follows the CRC checking algorithms described in [1].
    Since the length of the transport block could dynamically change, the number of tokens consumed at DataIn is set to the maximum block length plus the number of CRC parity bits attached, and the number of tokens produced at DataOut is set to the maximum block length. The maximum block length is determined by the TrCHType and TTI parameters.
  2. Each firing, a block of data with the CRC parity bits attached in reversed order is input for CRC checking, and the output block is the data block while the CRC parity bits have been removed. One token is consumed at pin TF, which acts as the instantaneous service rate indicator. So, the number of useful bits, or the length of input data block for CRC coding, is determined by TF. For details regarding transport formats, refer to General Signal Processing.
    One token is produced at pin CRCError: 0 indicates the result is correct; 1 indicates an error.

References
  1. 3GPP Technical Specification, TS 25.211, V3.0.0, "Physical channels and mapping of transport channels onto physical channels (FDD)," October, 1999.
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