We examine the modulation and signal processing aspect of communications assisted by
cooperative relay nodes in wireless ad hoc networks. Several distributed modulation,
detection, and combining schemes, utilizing either nonregenerative or regenerative relay
nodes, are reviewed and their performances in fading channels are discussed. These
schemes offer cooperative diversity against channel fading compared to their
noncooperative counterparts. They may or may not require knowledge of the channel state …

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 …