Cyclic Redundancy Check
The cyclic redundancy check is used for error detection in the payload bits. At the transmitter side, the CRCEncoder
is add the parity bits at the end of payload information. These parity bits are used by CRCDecoder at the receiver to
detect errors in the received payload bits. These parity bits are computed using a generator polynomial whose order is equal
to the number of parity bits. The 3GPP has standardized 6 generator polynomials for parity bits generation of certain length
which are used by the different physical chains. The details about these polynomials are given below.
|
Length |
Generator Polynomial |
Usage |
|---|---|---|---|
“CRC24A” |
24 |
\(g_{CRC24A}(D) = D^{24} + D^{23} + D^{18} + D^{17} + D^{14} + D^{11} + D^{10} + D^{7} + D^{6} + D^{5} + D^{4} + D^{3} + D + 1\) |
PDSCH, PUSCH-TB |
“CRC24B” |
24 |
\(g_{CRC24A}(D) = D^{24} + D^{23} + D^{6} + D^{5} + D + 1\) |
PDSCH, PUSCH(shared)-CB |
“CRC24C” |
24 |
\(g_{CRC24A}(D) = D^{24} + D^{23} + D^{21} + D^{20} + D^{17} + D^{15} + D^{13} + D^{12} + D^{8} + D^{4} + D^{2} + D + 1\) |
PDCCH, PBCH |
“CRC16” |
16 |
\(g_{CRC24A}(D) = D^{16} + D^{12} + D^{5} + 1\) |
PDSCH, PUSCH-TB |
“CRC11” |
11 |
\(g_{CRC24A}(D) = D^{11} + D^{10} + D^{9} + D^{5} + 1\) |
PUCCH, PUSCH(control)-CB |
“CRC6” |
6 |
\(g_{CRC24A}(D) = D^{6} + D^{5} + 1\) |
PUCCH, PUSCH(control)-CB |
The details about the implementation, usage and application interface is provided in following sections.
Table of Contents