Novel intentional puncturing schemes for finite-length irregular LDPC codes

In this paper, we investigate rate-compatible (RC) short/moderate length irregular low-density parity-check (LDPC) codes and propose three different novel puncturing schemes to determine the preferred puncturing positions so as to achieve less performance degradation. The first one is based on a short cycle counting algorithm as well as grouping variable nodes which have the equal length of short cycles in the Tanner Graph; the second scheme can be seen as an improved version of the first one by means of introducing another metric called Extrinsic Message Degree (EMD); and the last scheme relies on a simulation-based exhaustive search in order to find the best puncturing pattern among several random puncturing patterns. The simulation results show that all three proposed schemes can achieve the rate flexibility and minimize the performance loss over the additive white Gaussian noise (AWGN) channel.