Dynamic Resource Allocation with Precoding for OFDMA-Based Wireless Multicast Systems

In this paper, we consider a multi-antenna wireless multicast system with multiple multicast groups. The problem of resource allocation with downlink precoding for the multicast systems is studied, assuming the channel state information between transmit and all the receivers is available at the transmitter. Specifically, we formulate an optimization problem to maximize the system throughput given a set of available resources (power and subcarriers). A three-step algorithm is proposed, in which the multicast precoding process, subcarrier assignment and power allocation is operated separately to reduce the computational complexity. In two extreme cases, namely, low and high SNR regimes, the low-complexity allocation algorithm is further simplified. Simulation results also show that the system throughput is significantly improved by using our proposed algorithms both in multicast system and in unicast system.