7.3.2 CRC attachment
38.2123GPPMultiplexing and channel codingNRRelease 17TS
Error detection is provided on DCI transmissions through a Cyclic Redundancy Check (CRC).
The entire payload is used to calculate the CRC parity bits. Denote the bits of the payload by
, and the parity bits by
, where 
is the payload size and 
is the number of parity bits. Let 
be a bit sequence such that 
for 
and 
for 
. The parity bits are computed with input bit sequence 
and attached according to Clause 5.1 by setting 
to 24 bits and using the generator polynomial 
. The output bit 
is
for 
for 
,
where 
.
After attachment, the CRC parity bits are scrambled with the corresponding RNTI 
, where 
corresponds to the MSB of the RNTI, to form the sequence of bits 
. The relation between ck and bk is:
for k = 0, 1, 2, …, 
for k = 
, 
,
,…, 
.