Exploiting Self-Information to Improve the Performance of Multi-Way Relay Channels

Full data exchange with complex field network coding (CFNC) has been shown to achieve a throughput of 1/2 symbol per user per channel use (sym/U/CU) in a multiway relay channel (MWRC). Further, optimum precoding has been designed for a MWRC with a throughput of 1/2 sym/U/CU such that a rectangular quadrature amplitude modulation (QAM) constellation symbol is received. To achieve this throughput, any superimposed combination of user symbols must be distinguishable at the relay and users. In this paper, a decode-and-forward (DF) transmission scheme for full data exchange in a MWRC is presented which decreases the constellation size received by the users and hence leads to a downlink performance improvement. This is achieved by exploiting user self-information. It is also shown that the proposed DF transmission scheme leads to uplink performance improvement. The proposed transmission scheme is evaluated in both additive white Gaussian noise (AWGN) and Rayleigh fading channels.