5.1 CRC calculation
38.2123GPPMultiplexing and channel codingNRRelease 17TS
Denote the input bits to the CRC computation by 
, and the parity bits by 
, where 
is the size of the input sequence and 
is the number of parity bits. The parity bits are generated by one of the following cyclic generator polynomials:
– 
for a CRC length 
;
– 
for a CRC length 
;
– 
for a CRC length 
;
– 
for a CRC length 
;
– 
for a CRC length 
;
– 
for a CRC length 
.
The encoding is performed in a systematic form, which means that in GF(2), the polynomial:
yields a remainder equal to 0 when divided by the corresponding CRC generator polynomial.
The bits after CRC attachment are denoted by 
, where 
. The relation between 
and 
is:
for 
for 
.