دسته بندی مبتنی بر رادیو شناختی برای دسترسی طیف اشتراک گذاشته شده فرصت طلب به منظور افزایش طول عمر شبکه های حسگر بی سیم

In recent times, Cognitive radio (CR)-based wireless sensor networks (WSNs) have been widely used for opportunistic access of the shared spectrum. In WSNs, deployment of sensor nodes (SN) may be random, or it may follow an optimized approach-based upon the application in which it is to be used. Energy efficient route selection for transferring data from a SN to the base station (BS) is the key issue to increase the lifetime of WSN. Therefore, hierarchical cluster-based data transmission from a SN to BS using multi-hop communication can be one of the effective solutions, as the transmission operation consumes more energy compared to sensing or computation. Several mechanisms have been proposed in the literature for an improvement of network lifetime. Motivated from the above, in this paper, we propose a Distance-Based Multihop Clustering and Routing (DB-MCR) protocol for heterogeneous environment to improve stability, and network lifetime of WSNs. By fixing the node densities, network region is segmented into different subregions with a specific shape. Boundaries of the segmented regions are estimated using the node densities. Segment-wise data transmissions are used for data collection at BS which provides separate bands for the nodes in different regions. A distance-based algorithm is used for election of cluster heads (CH) in which a weighted election probability (WEP) is computed to reduce the interference among the nodes. The performance of the proposed scheme is evaluated using extensive simulations with respect to network lifetime, and stability. The results obtained at initial energy E0=0.25J with BS located at corner show that DB-MCR improves the lifetime by 13% & 17%, and stability by 8% & 16% in comparison to MCR and SEP respectively.