A Cooperative Modulation Scheme for Wireless Relay Networks

To exploit the cooperative diversity for wireless relay networks, signal space diversity can be combined with practical cooperative communication schemes. In this paper, we investigate cooperative modulation schemes at the symbol level based on fully decoding received signals at the bit level. We propose a novel decode-remodulate-and-forward (D-ReM-F) cooperative modulation scheme that works well with higher signal constellations when relay is close to source. Capacity analysis based on discrete QAM signal inputs for Rayleigh fading channels has been performed for this scheme as well as for amplify-and-forward (AF) scheme and repetition-based decode-and-forward (DMF) scheme. Simulation results have been shown to support the good performance of such cooperative transmission schemes both in slow fading and fast fading cases.