MPSK Symbol-based Soft-Information-Forwarding Scheme in Rayleigh Fading Channels

In this paper, we proposed a symbol-based multiple phase shift keying (MPSK) soft-informationforwarding (SIF) scheme for a two-hop parallel relay wireless network in Rayleigh fading channel. First the binary information streams at the source are mapped into MPSK symbols, and the relays construct the relay processing function by passing the intermediate soft decisions. Then the relays broadcast the processed symbols to the destination. After the maximum ratio combination, the received symbols at the destination can be decided by maximum-likelihood (ML) decision. Four MPSK symbolbased forwarding schemes are investigated and the simulation results show that the bit error rate (BER) performance of soft information forwarding scheme has better BER performance than the existing memoryless forwarding scheme based on MPSK modulation, and it is more practical than the SIF scheme based on BPSK modulation.