LLR Transmission Based Multiple Access Relay Channels with Non-coherent BFSK Modulations

In this paper, multiple access relay channel (MARC) where multiple users communicate with a common destination via a relay using ideas from network coding is considered. Noncoherent binary frequency shift keying (BFSK) is employed to eliminate the channel estimation cost of the system and loglikelihood ratio (LLR) of network coded symbol is transmitted from the relay terminal to mitigate error propagation. The bit error rate (BER) performance of the system over Rayleigh fading channels are obtained by simulation results and it is seen that MARC model based on noncoherent BFSK signaling and LLR transmission from the relay provides full diversity gain.