An efficient power allocation scheme in joint spectrum overlay and underlay cognitive radio networks

In this paper, we propose an efficient power allocation scheme that aims at maximizing the system throughput in joint spectrum overlay and underlay cognitive radio network. We show that our proposed scheme enlarges the achievable throughput region comparing to the overlay strategy, and causes less interference than the underlay strategy. In addition, since the unlicensed users adopting the overlay strategy do not necessarily have perfect sensing knowledge regarding the licensee, we modify the power allocation scheme with the imperfect sensing knowledge. The simulation results show that the proposed scheme can achieve better performances.