On Construction of Low-Density Parity-Check Codes for Ultra Reliable and Low Latency Communications

Low-density parity-check (LDPC) codes with protograph-based raptor-like (PBRL) structure have been chosen as the data channel coding scheme for the fifth-generation (5G) enhanced mobile broad band (eMBB) services. However, these 5G LDPC codes are not optimized for the scenarios of Ultra Reliable and Low Latency Communications (URLLC) and massive Machine Type Communications (mMTC) in which small transport block sizes are usually used. In this paper, a new method is proposed to construct PBRL LDPC codes for URLLC and mMTC. This method incorporates degree-distribution optimization, base matrix derived from parity-check matrix of quadratic residue codes, masking technique and modified progressive-edge-growth (PEG) algorithm. Simulation results show that the proposed PBRL LDPC codes outperform 5G LDPC short codes in terms of error-correcting performance.