An optimal spectrum sharing method for MIMO cognitive radio networks

This paper investigates the resource optimization problem for the multiple-input multiple-output (MIMO) cognitive radio (CR) networks. Different from the conventional works, a novel optimization metric, namely the bandwidth-power product (BPP), is used to achieve the optimal spectrum sharing. We apply the direct-channel singular value decomposition (DC-SVD) method to design the optimal source precoding matrix. Then the unified power and channel allocation problem is derived and found to be a mixed-integer programming problem. Hence, a sub-optimal and tractable algorithm with low complexity called the joint iterative power and channel optimization (JIPCO) algorithm is proposed. Furthermore, the discrete particle swarm optimization (DPSO) algorithm is introduced to approximately provide an upper bound. Numerical results show that the JIPCO algorithm achieves the acceptable performance with great reduction of computation complexity and validate the superiority of the proposed scheme compared to conventional power optimization scheme using the water-filling method.