Resource allocation with beamforming technique for MDC multicast in OFDM-based CRNs

In this paper, we study a resource allocation scheme for downlink orthogonal frequency division multiplexing (OFDM) cognitive radio networks (CRNs) in which the cognitive base station (BS) is equipped with multiple antennas. The multiple description coding multicast (MDCM) model and beamforming technique are employed to maximize the total received rate of all cognitive radio (CR) users with the constraint on total transmission power and interference threshold to primary user (PU). This paper proposes a two-step suboptimal scheme to conduct the resource allocation: firstly, the beamforming vector (BY) and the subset of each multicast group (MG) are obtained with a heuristic approach, and then the transmission power and subcarńer allocation is realized by the dual optimization method. It has been verified in the simulation results that the proposed scheme performs better on both throughput maximization and interference management.