A Convex optimization for sum rate maximization in a MIMO cognitive radio network

Cognitive radio is a promising approach that allows a secondary system to reuse radio resources assigned to a primary system. In a cognitive system, it is challenging to design a precoding scheme for the secondary system such that the sum rate of the secondary system is maximized while meeting interference constraints for the primary system. In this paper, we first formulate a sum rate maximization problem for the secondary system. We then use block matrices to modify the problem in the unique form of constraints. Numerical results show that the proposed optimization is efficient for sum rate maximization in a cognitive radio system.