Layered randomized cooperative multicast for lossy data: A superposition approach

In this paper, we consider randomized distributed cooperation for multicasting a source signal with end-to-end distortion used as a performance metric. In order to provide differentiated quality to users with different channel strengths, we study layered cooperation where layers are transmitted simultaneously using superposition coding. We first formulate the problem and investigate the effect of power allocation of different layers on the distribution of end-to-end quality of users under a real-time delivery requirement. We then compare the proposed scheme with sequential layered transmission in which the layers are transmitted sequentially in time. Our results show that layered cooperation with superimposed layers outperforms sequential layered cooperation and provides a good alternative for multicast applications.