Distributed event driven cluster based routing in cognitive radio sensor networks

Cognitive radio sensor network (CRSN) is a combination of wireless sensor network (WSN) and opportunistic spectrum access technology. It involves the issues related to energy and dynamic spectrum inherited by WSN and cognitive radio network (CRN) respectively. CRSN poses research challenges in designing an efficient topology control for communication in network. In this paper, we propose an event-driven cluster based routing approach for CRSN that jointly considers both the energy and dynamic spectrum challenges. Reported schemes for CRSN suffer from high frequency of re-clustering due to PU activities and are energy inefficient. The proposed scheme employs a self-organized distributed clustering to obtain less average node power by producing the optimal number of clusters. To mitigate the effect of PUs' activities, our proposed scheme forms clusters having more number of common channels. To enhance inter-cluster connectivity, our proposed scheme selects gateway nodes having more number of common channels with neighboring nodes. Furthermore, a cluster-head (CH) rotation mechanism is employed that picks the CH based on nodes' residual energy values, available channels, neighbors and distance to the sink in order to have longer network lifetime. Upon detection of an event, the proposed scheme aims to route the event samples through an energy efficient and stable path from source node to the sink node. On performance evaluation, we found that our proposed scheme outperforms in terms of energy consumption, packet delivery ratio and stability of selected gateway nodes than considered competitive approaches.