Crate cai_cyclic [−] [src]
The generator polynomial for the base code is given by
g(x) = x8 + x5 + x4 + x3 + 1
It can detect up to 4 errors or correct up to 2 errors.
The DMR air interface extends this code to (18, 9, 6) with an extra parity check bit
in the LSB, then shortens it to (16, 7, 6) by deleting two MSB data bits. The extra
parity bit is computed over the data bits using the mask
The P25 air interface shortens this code to (16, 8, 5) by deleting the MSB data bit.
The decoding algorithm is based on the algorithm described in Lin and Costello's Error Control Coding (1983) and Roman's Coding and Information Theory (1992), p345.
Try to decode the given 17-bit word to the nearest codeword, correcting up to 2 errors.
Encode the given 9 data bits into a 17-bit codeword.