Smart Relay Opportunistic Spectrum Sharing in Energy Efficient Cognitive Radio Networks

Opportunistic spectrum sharing (OSS) and cooperative spectrum sharing (CSS), as the most popular dynamic spectrum accessing (DSA) technologies, are effective methods to improve the spectrum efficiency (SE) and the energy efficiency (EE). However, most of previous researches about OSS and CSS focus on SE and few of researches are concerned about EE. Moreover, both OSS and CSS have their own disadvantages. OSS provides no benefit for the primary user, while CSS needs a cooperative model, though it leads to a win-win situation for the primary user and the secondary user. These disadvantages limit the performance of OSS and CSS in applications. In this paper, a smart relay opportunistic spectrum sharing (ROSS) model is designed. Based on the advantage of full-duplex transceiver, the ROSS model simultaneously improves EE of the primary user and the secondary user without imposing any cooperation. Furthermore, although we take EE as optimal goal, numerical results show that SE increases as well.