Virtual full-duplex relay selection in relay-assisted cognitive radio networks

In this paper, we propose a virtual full-duplex relay selection scheme in order to improve the achievable rate of secondary system in relay-assisted undelay cognitive radio (CR) networks. The proposed scheme first allocates transmit powers of transmitting nodes considering the interference constraint given by the primary system. Then, the best transmitting and receiving relay pair is selected based on max-max relay selection criterion. It is evaluated through simulations in terms of the average end-to-end rate, compared with the state-of-the art half-duplex relay selection scheme for CR networks. The results show that the proposed scheme can achieve almost the double rate by removing a half-duplex limitation. In addition, the effects of number of relays and buffer size are also provided.