On Construction of Rate-Compatible Raptor-Like QC-LDPC Code for Enhanced IDMA in 5G and Beyond

Recently, rate-compatible raptor-like quasi-cyclic low-density parity-check (RL-QC-LDPC) codes have been adopted in 5G new radio technical specification. This paper is focused on the construction of rate-compatible RL-QC-LDPC codes for enhanced interleave-division multiple-access (IDMA), while taking the good features of 5G new radio LDPC codes into consideration. Firstly, a rate-compatible RL-QC-LDPC code family is optimized for point-to-point transmission via progressive matrix growth algorithm. Enhanced IDMA with this code family shows good performance at relatively low sum spectral efficiency. Secondly, this code family is optimized for enhanced IDMA via row-by-row extension for different spectrum efficiency requirements. With the optimized code families, enhanced IDMA is capable of supporting much higher sum spectral efficiency and user loads. Finally, the finite-length performance of enhanced IDMA with these code families are verified by bit error rate simulations.