# nrCRCEncode

Calculate and append cyclic redundancy check (CRC)

Since R2018b

## Description

example

blkcrc = nrCRCEncode(blk,poly) calculates the CRC defined by the polynomial poly for the input data blk. The function returns the CRC encoded data, which is a copy of the input data with the CRC parity bits appended. For details on the associated polynomials, see TS 38.212 Section 5.1 [1].

example

blkcrc = nrCRCEncode(blk,poly,mask) applies a logical difference (XOR) mask on the appended CRC bits with the integral value of mask. The appended CRC bits in blkcrc are XOR-masked with the most significant bit (MSB) first to the least significant bit (LSB) last. The masked CRC is of the form (p0 xor m0), (p1 xor m1),…, (pL-1 xor mL-1), where L is the number of parity bits, and p0 and m0 are the MSBs in the binary representation of CRC and mask, respectively. If the mask value is greater than 2L - 1, the L LSBs are considered for the mask.

## Examples

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Calculate and append CRC parity bits to an all-zeros matrix of two data blocks. The result is an all-zeros matrix of size 124-by-2.

blkcrc = nrCRCEncode(zeros(100,2),'24C');
any(blkcrc(:,1:2));

Calculate and append masked CRC parity bits to an all-zeros matrix of two data blocks. The appended CRC bits are XOR-masked with the specified mask, from the MSB first to the LSB last. The result is an all-zeros matrix apart from the elements in the last position.

blkcrc(end-5:end,1:2)
ans = 6×2

0     0
0     0
0     0
0     0
0     0
1     1

## Input Arguments

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Input data, specified as a matrix of real numbers. Each column of the matrix is treated as a separate data block.

Data Types: double | int8 | logical

CRC polynomial, specified as '6', '11', '16', '24A', '24B', or '24C'. For details on the associated polynomials, see TS 38.212 Section 5.1.

Data Types: char | string

XOR mask, specified as a nonnegative integer. The mask is typically a radio network temporary identifier (RNTI).

Data Types: double

## Output Arguments

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CRC encoded data, returned as a matrix of real numbers. blkcrc is a copy of the input blk with the CRC parity bits appended. Each column corresponds to a separate CRC encoded code block. blkcrc inherits its data type from the input blk.

Data Types: double | int8 | logical

## References

[1] 3GPP TS 38.212. “NR; Multiplexing and channel coding.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.

## Version History

Introduced in R2018b