Participation in Repeated Cooperative Spectrum Sensing: A Game-Theoretic Perspective

In cognitive radio networks (CRNs), cooperative spectrum sensing (CSS) is usually performed periodically due to the uncertain activity of primary users (PUs). Considering the overhead in performing CSS, a selfish secondary user (SU) may not always participate in CSS. Instead, it elaborately selects a frequency (or number of times) for CSS participation to maximize its interest. A fusion center then schedules it to conduct CSS in appropriate periods. This paper investigates the interactive decision on the CSS participation frequency under sensing performance and quality of service (QoS) requirements. The problem is formulated as a noncooperative game, where Nash Equilibrium (NE) corresponds to the desired frequency selection outcome. Since the strategy sets of SUs are coupled, obtaining directly the NE requires explicit coordination among SUs, which is unrealistic in practice. Alternatively, we decompose the game into a lower-level uncoupled game and a higher-level optimization problem. A distributed hierarchical iterative algorithm (DHIA) is then proposed to obtain the desired frequency selection outcome without requiring explicit coordination. Furthermore, the uncertain sensing performance of SUs and the fairness issue are also considered. Finally, numerical results validate the effectiveness of the proposed scheme.