Joint message passing decoding for LDPC codes with CCDMs

In this Letter, message passing algorithms are introduced to jointly decode low-density parity-check (LDPC) codes and constant composition distribution matchers (CCDMs) to achieve better performance. Then, based on the weight constraint of CCDMs, a weight decoding with linear complexity is proposed to efficiently decode the CCDM codewords. Simulations over a fiber channel show that short CCDMs with the proposed joint decoding provide up to 10.6% reach increase compared with long CCDMs with one-pass decoding.