Cooperative spectrum sensing via relay-assisted random broadcast in cognitive smartphone networks

Cognitive smartphone network (CSN), the smartphone network with cognitive radio features, has been advocated as an effective approach to improve the transmission bandwidth. Compared with the traditional smartphone network, cooperative spectrum sensing (CSS) is a special technique of smartphone sensing, however, is still an open issue. In this paper, we consider a practical power-limited cluster-based CSN, in which one end user can only share the sensing messages broadcasted by its neighbors. Aiming at improving the performance of CSS, we propose a relay-assisted random broadcast scheme to extend the range of message sharing. We introduce the message sharing probability (MSP) to quantify the performance of message sharing, and the restricted random broadcast model to simplify the theoretical analysis of MSP. We then employ the proposed scheme for CSS in a CSN, and study the problem of sensing–sharing tradeoff. Simulations show that our proposed scheme can achieve substantial performance improvement on both message sharing and CSS compared to the scheme without relays. Moreover, it is indicated that the performance of CSS can be maximized by optimizing the duration of message sharing when a total sensing time is given.