Layered randomized cooperation for multicast

Cooperation of wireless users is known to provide substantial improvements in channel reliability and in end-to-end distortion. User cooperation is especially attractive for multicast since the relays are also part of the intended recipients. In this paper, we consider a randomized distributed cooperation scheme for multicasting a source signal. Using end-to-end distortion as a performance metric and assuming a delay constraint, we investigate the relation among the decoding SNR threshold, number of hops, coverage range and the distribution of end-to-end quality over users in the coverage range. In order to provide differentiated quality to users with different channel strengths, we further employ layered cooperation and illustrate the benefits.