Crate comnum_fec 

comnum-fec — channel coding

Codes take information bits and return coded bits; decoders take log-likelihood ratios (positive for a 0, the convention of the whole library) and return the decided information bits. Every code implements block::BlockCode and the verb traits Encode and Decode; the LDPC, convolutional, turbo and NR LDPC codes (punctured or not) also give the a posteriori LLRs of their information bits (block::SoftDecode).

Module	Content
crc	cyclic redundancy checks of 5G NR (CRC24A/B/C, CRC16, CRC11, CRC6)
scrambling	the Gold scrambler of 3GPP TS 38.211 (its sequences are comnum_math::sequences)
interleaving	block, random and QPP interleavers
conv	convolutional codes: trellis, Viterbi (soft and hard), BCJR (log-MAP, max-log)
turbo	turbo codes (two $(13, 15)_{8}$ recursive codes, LTE) with iterative decoding
ldpc	LDPC codes: progressive edge growth, repeat-accumulate codes, alist files, belief propagation, (normalised and offset) min-sum, layered scheduling
ccdm	constant-composition distribution matching (uniform bits to a shaped symbol sequence)
bch	shortened binary BCH codes (the outer code of DVB-S2) with Berlekamp–Massey decoding, over the fields of comnum_math::gf2m
rs	Reed–Solomon codes: systematic encoding, errors-and-erasures decoding, shortening, closed-form error rates
puncture	puncturing of the convolutional and turbo codes (802.11, DVB-S patterns), the bit selection of a rate matching, free distance of punctured codes
polar	polar codes: Gaussian-approximation construction, SC and CRC-aided SC-list decoding
ccsds	the codes of CCSDS 131.0-B (TM synchronization and channel coding): Reed–Solomon in the dual basis with interleaving and virtual fill, the (8160, 7136) and AR4JA LDPC codes, the 16-state turbo codes
nr	the codes of 5G NR (TS 38.212): the LDPC code of the data channels and the polar code of the control channels, with their rate matching
bounds	the capacity of the binary-input AWGN channel and the normal approximation of the error probability at finite length
block	the BlockCode interface and the soft output SoftDecode

Modules

bch

Binary BCH codes, shortened: the outer code of DVB-S2 (comnum_systems::dvbs2).

block

The interface shared by the block codes.

bounds

Information-theoretic limits of binary codes on the AWGN channel.

ccdm

Constant-composition distribution matching (CCDM): uniform bits to sequences of symbols of a prescribed distribution, the shaping stage of probabilistic amplitude shaping (comnum_systems::pas).

ccsds

The channel codes of CCSDS 131.0-B-5 (TM Synchronization and Channel Coding): the Reed–Solomon codes in the dual basis with their interleaving and virtual fill, the (8160, 7136) LDPC code, the AR4JA LDPC codes and the turbo codes.

conv

Convolutional codes: trellis, Viterbi and BCJR decoders.

crc

Cyclic redundancy checks.

interleaving

Interleavers: permutations of the coded bits (or of their LLRs).

ldpc

Low-density parity-check (LDPC) codes.

nr

The channel codes of 5G NR (3GPP TS 38.212): the LDPC code of the data channels (NrLdpc) and the polar code of the control and broadcast channels (NrPolar), with their rate matching, from the tables of the standard (tables).

polar

Polar codes.

puncture

Puncturing of the convolutional and turbo codes: rate-compatible patterns, the punctured block codes and the free distance of a punctured code.

rs

Reed–Solomon codes over $\mathrm{GF}(2^{m})$: systematic encoding, errors-and-erasures decoding, shortening.

scrambling

Scrambling by the length-31 Gold sequence of 3GPP.

turbo

Turbo codes: two recursive systematic codes in parallel, decoded iteratively.