Distributed modulation for cooperative wireless communications

This paper examines the modulation aspect for data forwarding in wireless relay networks. We consider both distributed coherent and distributed differential detection schemes to handle two different cases when the channel state information (CSI) can be reliably estimated at the receiving nodes and when it cannot. We analyze both amplify-and-forward and decode-and-forward relaying schemes and derive the corresponding average bit error rates (BER) in Rayleigh fading channels. Analysis and simulation results show that the discussed distributed coherent/differential scheme are capable of providing cooperative diversity gain at destination node, one of of an appealing features for distributed relaying systems.