Reputation-based hierarchically cooperative spectrum sensing scheme in cognitive radio networks

Cooperative spectrum sensing helps improving the detection performance of primary user for a cognitive radio network in a significant way. Meanwhile, the introduction of cluster-based hierarchical cooperation can reduce the overhead obviously. Although hierarchically cooperative spectrum sensing has been widely investigated, researchers seldom consider the robustness problem of the system. In this paper, a reputation-based hierarchically cooperative spectrum sensing scheme is proposed. In our proposed scheme, there are two levels of cooperation, the first one is performed within a cluster and the other is carried out among clusters. With the reputation mechanism in the second-level cooperation, the proposed scheme can not only relieve the influence of multipath fading and shadowing but also eliminate the impact of the primary user emulation attack on a relatively large scale. Simulation results show that in the scenarios with deep-shadowing or multiple attacked users, our proposed scheme achieves better robustness compared with those conventionally cooperative solutions.