Adaptive power and rate allocation for mobile multicast throughput optimization over fading channels in wireless networks

We investigate adaptive power and rate allocation schemes for multicast over fading channels in wireless networks. Specifically, we take advantage of the superposition coding to achieve high multicast throughput, where the transmitted signal consists of multiple parallel sub-stream signals. Each receiver decodes the sub-stream signals within its decoding capability determined by the received signal to noise ratio (SNR). Under the above architecture, we first formulate the multicast throughput optimization problem to obtain the power allocation policy for each sub-stream signal subject to the total power constraint. Also, we develop a selective retransmission strategy to guarantee all receivers to recover the same data copy without unnecessary data reception. By introducing the concept of compensation ratio, we derive the optimal power allocation policy of the formulated throughput optimization problem for the two-receiver scenario. Numerical results are also presented to show the throughput improvement over the worst-case SNR-dominating (WSD) rate policy, the best-case SNR-dominating (BSD) rate policy, and the constant-rate policy.