Design of LDBCH Codes for Ultra Reliable Low Latency Communications

Abstract

In ultra reliable low latency communications, the demanding requirements on high reliability and low latency make it a challenge to design capable channel codes. In this work, a candidate named low-density BCH-constraint (LDBCH) code is introduced, which generalizes low-density parity-check codes by replacing the single parity check code constraints with the BCH code constraints. Specifically, a design methodology is introduced to construct efficient LDBCH codes of short information lengths and low coding rates. Moreover, the message passing decoding of LDBCH is enhanced by max-log approximation and weighted scaling when updating the BCH check nodes. Numerical results show that, with tolerable increase of decoding complexity, LDBCH codes with the proposed decoding enhancement outperforms CA-Polar and 5G LDPC by about 0.3 dB and 0.5 dB in SNR, respectively, for the information length of 104 and the block error rate of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">- 6</sup> over an AWGN channel with QPSK modulation.