Efficient Convex Optimization for Beamforming in Cognitive Radio Multicast Transmission
In this paper, a novel algorithm for transmit beamforming to single co-channel multicast group is presented. The problem of minimizing the total power transmitted by the antenna array subject to interference constraints at the primary receivers and Quality-of-Service (QoS) constraints at the secondary receivers is addressed. It is shown that this problem, which is non-convex NP-hard, can be approximated by a convex Second-Order Cone Programming (SOCP) problem. Then, an iterative algorithm in which the SOCP approximation is successively refined is proposed.