Energy-efficient and trust-aware cooperation in cognitive radio networks

In this paper, a cooperative framework in cognitive radio networks, which addresses energy efficiency of the primary users (PUs) and trustworthiness of secondary users (SUs), is proposed. Specifically, the cooperation involves a PU selecting the most suitable SU as the cooperative relay and allocating the spectrum access intervals for relaying its message and rewarding the SU for its help in relaying the PU´s message. Based on the PU´s strategy, the selected SU determines its optimal transmission power. The above sequential decision procedure, with the PU as the leader and the SU as the follower, is formulated as a Stackelberg game. The outcomes of the proposed cooperative strategy, including partner selection, cooperation in an untrustworthy environment, and energy efficiency consideration, are analyzed. Numerical results demonstrate that, with the proposed relay selection scheme, the PU can achieve high energy saving through cooperation with the trustworthy SU.