Multi-resolution signaling for multimedia multicasting

This article develops two selective repeat automatic repeat request (SR-ARQ) schemes, which exploit the difference in bit protection levels of M-PSK symbols with Gray code mapping to improve the throughput performance of multimedia multicasting in fading channels. The throughput enhancement is achieved by optimizing the phase offset ratio of nonuniform constellations matched to the difference in QoS requirements for multimedia traffic and link qualities among nodes in a multicast group. The preliminary results of our research are encouraging and provide motivation for further research on leveraging the benefits of nonuniform constellations on higher layers of the protocol stack. i.e., to facilitate efficient multimedia multicasting in wireless networks.