Joint power control and spectrum access in cognitive radio networks

Cognitive Radio (CR) is proposed to overcome the problem of spectrum underutilization and congestion caused by the increasing demand of wireless services and applications. It is still a challenge to improve the spectrum efficiency of the secondary network for Secondary (unlicensed) Users (SUs) and avoid imposing interference to the Primary (licensed) Users (PUs). In this paper, we propose a joint power control and spectrum access scheme for the CR network. By addressing the power allocation problem and exploiting a Dynamic Spectrum Access (DSA) scheme (which is based on the power allocation and also aims at improving the secondary network throughput) from a cooperative-game perspective, our joint scheme can improve the throughput of the secondary network and guarantee the SUs׳ fairness, without imposing overlarge interference to the PUs. Numerical results reflect that, compared with previous studies, our joint power control and spectrum access scheme presents advantages in comprehensive performance (e.g., spectrum efficiency, fairness and throughput). Beyond a theoretical framework, we solve the optimization problem with the Differential Evolution (DE) algorithm which is more feasible to be implemented in practice.