Interference Minimization with Power-Capacity Constraints for Cognitive Radio Networks

Cognitive radio (CR) is a technology which can solve the scarcity and inefficiency of spectrum usage. It achieves this target by enabling the licensed and unlicensed users to share the same spectrum under the condition that the unlicensed user must minimize the power interference produced on the licensed user through using multiple antennas for the transmitters and receivers. This paper introduces the Interference management problem of a CR network for minimizing the interference power introduced to licensed receiver while satisfying capacity and power constraints for unlicensed user transmission. An algorithm is developed that converges to the optimal solution after a few several iterations. Performance of (4×4), (8×8) and (16×16) Multiple-Input Multiple-Output (MIMO) systems with different power constraint values are compared.