Decode-based differential modulation for wireless relay networks

In this paper, we develop a differential binary phase shift keying (BPSK) modulation scheme for wireless relay networks composed of one source, one relay and one destination node. The proposed scheme, referred to as the differential decode-and-forward (DDF), utilizes the relay to assist data transmission from the source to the destination. We derive a maximum likelihood (ML) detector and a piece-wise linear (PL) detector for the proposed DDF scheme. A closed-form bit error rate (BER) expression is presented for the proposed PL detector. Both analytical and simulation results show that the proposed DDF scheme is capable of providing diversity gain at the destination node over Rayleigh fading channels.