Modulation-Adaptive Cooperation Schemes for Wireless Networks

Cooperative communications can exploit the distributed spatial diversity-gain to improve the link performance. In this paper, we investigate the application of adaptive modulation concept to the decode-and-forward (DF) based cooperative network. With the relay nodes geographically close to the destination, we assume the perfect channel feedback is available only at the relay nodes, and propose a class of novel modulation-adaptive cooperation schemes (MACSs). The proposed schemes are first investigated in the single-relay scenario, and then extended to the multi-relay scenario. Simulation results show that the proposed schemes can offer the significant throughput-improvement in comparison with conventional DF systems.