Distributed joint source-channel coding for relay systems exploiting spatial and temporal correlations

In this paper, we propose a distributed joint source-channel coding (DJSCC) strategy to exploit spatial and temporal correlations simultaneously for transmitting binary Markov sources in a one-way relay system. The relay only extract and forward the source message to the destination, which implies imperfect decoding at the relay. The probability of errors occurring in the source-relay link can be regarded as spatial correlation between source and relay nodes. This spatial correlation can be estimated at the destination node and utilized in the iterative processing. In addition, the knowledge about the temporal correlation of the Markov source is also utilized at the destination. A modified version of the BCJR algorithm is derived to exploit the temporal correlation. Furthermore, extrinsic information transfer (EXIT) chart analysis is performed to investigate convergence property of the proposed technique with the aim of the suitable code design. Simulation results for bit error rate (BER) performance and EXIT chart analysis show that, by exploiting the spatial and temporal correlations simultaneously, our proposed technique achieves significant performance gain, compared with the case where the correlation knowledge is not fully used.