Interference Mitigation Using Power Control in Cognitive Radio Networks

One of the challenging problems of cognitive radio networks is the interference which occurs when a cognitive radio accesses a licensed band but fails to notice the presence of the licensed user. To allow the cognitive radio to access the same spectrum band where the primary user is operating creates a problem, the cognitive radio may interfere with the primary system, and hence degrading the quality of service for the primary receiver. This paper presents an adaptive power control scheme for cognitive radio. The proposed scheme estimates the distance between the primary user and the cognitive radio, using the SNR as proxy for distance. On the basis of this information the cognitive radio adaptively changes its maximal transmit power to prevent the primary user from harmful interference. Numerical results are presented to demonstrate the effectiveness of the proposed algorithm.