Cooperative Spectrum Sensing Protocols for Cognitive Radio Mesh Networks

In this paper, we consider the cooperative spectrum sensing problem in a cognitive radio (CR) mesh network, where secondary users (SUs) are self-organized into a IEEE 802.16 mesh network sharing the spectrum band allocated to a primary users’ (PUs) network. We propose two new cooperative spectrum sensing strategies, called amplify-and-relay (AR) and detect-andrelay (DR), aiming at improving the SU’s detection performance with the help of other eligible SUs so as to agilely vacate the channel to the primary network when PUs stay in the active states. AR and DR strategies are implemented by two cooperative detection protocols named as AR Protocol (ARP) and DR Protocol (DRP), respectively, which are arranged to periodically execute in the spectrum sensing phase of a MAC frame. For each protocol, we derive the closed-form expressions of false alarm and detection probabilities for both the singlerelay and multi-relay models, with or without channel state information (CSI). Simulation results show that our proposed protocols achieve better performance than a non-cooperative or non-relay spectrum sensing approach and an existing cooperative detection protocol. As expected, we observe that the detection performance improves as the number of eligible relay SUs increases, and is better for the known-CSI case than that of the unknown-CSI case.