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WCDMA3G_CRCEncoder


Description: Add CRC to each transport block
Library: 3GPPFDD 10-99, Channel Coding
Class: SDFWCDMA3G_CRCEncoder

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

one transport block without CRC bits

int

2

TF

transport format

int

Pin Outputs

Pin

Name

Description

Signal Type

3

DataOut

one transport block with CRC attatched

int

Notes/Equations
  1. The model is used to add CRC parity bits to a block of transport channel data.
    Signal processing follows the CRC checking algorithms described in [1] section.
  2. Since the length of the transport block could be dynamically changing, the number of tokens consumed at DataIn is set to be the maximum block length, and the number of tokens produced at DataOut is set to be the maximum block length plus the number of CRC parity bits attached.
    The maximum block length is determined by the TrCHType and TTI parameters.
    Each firing, a block of data is input for CRC checking; the output block consists of the input data block and the parity bits attached in reversed order. 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.

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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