EXIT-Chart-Aided Joint Source Coding, Channel Coding, and Modulation Design for Two-Way Relaying

In this paper, we have proposed and investigated an attractive joint source coding, channel coding, and modulation (JSCM) scheme for a two-way relaying system. We commence by quantifying the achievable capacity of the corresponding two-way relay channel before proposing low-complexity source coding schemes for concatenation with band-width-and power-efficient coded modulation schemes. Extrinsic information transfer (EXIT) charts are used to investigate the decoding convergence of the joint source and channel decoder and for the overall system design. The quality of the decoded source signals is quantified using the bit error ratio (BER) metric. It is found that the two-way-relay-based JSCM scheme is capable of attaining a combined coding and relaying gain of 5.7 dB over the conventional noncooperative JSCM scheme when communicating over uncorrelated Rayleigh fading channels in an outdoor environment.