WCDMA3G CRCEncoder

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WCDMA3G_CRCEncoder

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

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	Name	Description	Signal Type
1	DataIn	one transport block without CRC bits	int
2	TF	transport format	int

Pin	Name	Description	Signal Type
3	DataOut	one transport block with CRC attatched	int

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.
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.

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