Distributed source coding for multimedia multicast over heterogeneous networks

Real-time multimedia multicast over wireless networks is an exciting application that has generated a lot of interest recently. Its main challenge lies in the stringent bandwidth and time-delay requirements of real-time multimedia and severe impairments of the wireless channels. We develop a network-aware cross-layer design for multimedia multicast over heterogeneous wireless-wireline networks, that leverages the knowledge on network information theory, multimedia processing, error control, and networking. In particular, the encoded multimedia data are broadcast to multiple Internet servers over a wireless radio link. Each server merely compresses the signal it has received using distributed source coding by exploiting mutual correlation among signals received at different servers. The receiver collects bitstreams from the servers before performing joint decoding. We provide an algorithm for optimal nonuniform scalar quantizer design at the server side that minimizes the required rate under the decoder bit error rate constraint. For scalable multimedia codes, we develop a joint source-channel coding scheme which combines error-protection at the base station and distributed source coding at the servers. Our experimental results show significant performance improvements over conventional solutions due to spatial diversity and distributed source coding gains.