Optimal User Group Size for Fixed Channel Allocation in Multicast OFDM Systems

Broadcast/multicast services were proposed to enhance bandwidth efficiency for multimedia streaming services. Although dynamic channel allocation can achieve better system throughput, it suffers from extremely high real-time computational complexity and a heavy communication load. By contrast, fixed channel allocation is an attractive and feasible approach, which significantly relieves the limitations. In this work, we investigate the optimal size of a multicast group that maximizes the average overall system throughput for a multicast OFDM system based on fixed channel allocation. The optimal group size can be determined beforehand and only limited real-time computation is required. We prove that finding the optimal group size can be modeled as a standard convex optimization problem.