Channel and power allocation in cognitive radio networks

This paper investigates the power allocation between channels in a cognitive wireless network, using the spectrum underlay strategy where the primary users (PUs) and the cognitive users (CUs) coexist and operate in the same spectrum. We propose power allocation schemes to maximize the capacity of the overall system under the constraint that the interference to the PUs due to the CUs will not exceed a certain threshold, so that the communication of the PUs will not be affected. A mathematical optimization equation is first obtained, and then the system capacity of both the PUs and the CUs are compared using different channel and power allocation schemes. Simulation results show that the proposed scheme provides a significant improvement on the system capacity.