A resource allocation scheme for D2D multicast with QoS protection in OFDMA-based systems

A resource allocation scheme involving several Device-to-Device (D2D) multicast groups underlaying OFDMA-based systems is proposed in this paper. In order to guarantee Quality of service (QoS) of cellular users (CeUEs), we define the signal-to-interference-pulse noise ratio (SINR) threshold value for CeUEs. Meanwhile, the minimum throughput of a single D2D multicast group is predetermined to maintain fairness of each D2D multicast group. Since the subcarrier assignment and power allocation are a joint optimization problem with complex calculation, the proposed scheme is divided into two steps. First, subcarriers are allocated under the premise of ensuring the minimum throughput of the D2D multicast groups and the QoS of CeUEs. Then by applying an approximation form of Shannon capacity, the power allocation problem can be solved by convex optimization. Simulation results show that the proposed scheme improves sum-throughput significantly as well as fairness. Besides, the sum-throughput increases with the increasing number of D2D multicast groups.