Resource management in multicast OFDMA with proportional data rate and BER constraints

The resource allocation problem for the downlink of orthogonal frequency division multiple access (OFDMA) wireless multicast systems is investigated. It is assumed that both the base station (BS) and a user are equipped with a single antenna, and the allocation unit is not the subcarrier, as in conventional OFDMA systems, but a set of contiguous subcarriers referred to as a "chunk". The multicasting technology is able to support several groups of users with flexible quality of service requirements. A general mathematical formulation is provided, but achieving the optimal solution has a high computational cost. Thus, a heuristic but efficient algorithm is proposed in order to maximize the total throughput; the novelty of this algorithm is that it is subject to constraints on the total available power, the average bit error rate over a chunk, and proportional data rates among multicast groups. In addition, it considers different user classes with distinct QoS requirements. Simulation and complexity analysis are provided to support the benefits of chunk-based resource allocation to multicast OFDMA systems with tight QoS constraints for user classes.