Multi-hop Cluster Based Cooperative Spectrum Sensing Approach for Cognitive Radio Networks

Spectrum sensing is a key function in cognitive radio networks to detect vacant frequency bands for secondary (unlicensed) users without causing any interference to the transmission of primary (licensed) users. Due to the destructive conditions of sensing channel such as multipath fading and shadowing, a local sensing may not be able to meet the requirements for reliable sensing. Therefore, cooperative spectrum sensing is introduced to detect the primary user more accurately. Clustering approach is considered as an effective method that used in cooperative spectrum sensing to tackle the degradation in the performance of spectrum sensing due to fading and shadowing of reporting channel, and also to reduce the control channel overhead when the number of cooperative users becomes very large. However, most existing cluster-based cooperative spectrum sensing approaches are based on one-hop communication between the cluster heads and the fusion centre, which are suitable for small-scale networks. In practice, the fusion centre is usually located far away from the primary networks in the case of large-scale cognitive radio networks, which leads to some cluster heads to be far from the fusion centre. Such a case, the distant cluster heads will need more power to report their cluster results to the fusion centre, also may deteriorate the overall sensing performance at the fusion center due to reporting errors. In this paper, we propose a multi-hop cluster-based cooperative spectrum sensing scheme using Centralised Low Energy Adaptive Clustering Hierarchy (LEACH-C) protocol in order to reduce the power consumption and prolong the network’s lifetime, as well as improving the sensing performance. The simulation results show that our algorithm can achieve better energy gains as well as less delay than conventional cooperative spectrum sensing algorithms.