The sensitivity of joint source-channel coding based on double protograph LDPC codes to source statistics

Although the joint source and channel coding (JSCC) systems constructed from double protograph low-density parity-check (DP LDPC) codes has been demonstrated to possess good performance, especially when they are applied into the transmission of radiography images, where the frameworks of both transmitter and receiver still need to be further optimised for the sake of achieving bit error rate (BER) performance under 10^-6 over wireless transmission environment. This paper focuses on the perspective of transmitting terminal to investigate what factors will affect the performance of DP LDPC schemes so that the new transmitting models can be further designed. Specifically, this paper mainly concentrates on the sensitivity of DP LDPC scheme to source statistics. The simulation results show that the entropy of source information is a dominate factor for sources with low entropy while the correlated side information plays a vital role in sources with large entropy, which provides explicit directions for further JSCC coding structures optimisation.