Energy Efficient and Collision Reduction Routing Method for Wireless Sensor Networks Using Cognitive Radio

Working in ISM band becomes overcrowded, shared unlicensed spectrum band, leads to a reduction in the quality of communication. This makes increase in packet loss caused by collisions and results in the necessity of packets retransmissions. In wireless sensor networks a large amount of energy of sensor nodes will be wasted during retransmissions. Cognitive radio is the technology makes it possible for sensor nodes to make use of licensed bands. In this paper a routing technique for cognitive radio wireless sensor networks is presented, that is based on a cross-layer design that jointly considers route and spectrum selection. This method has two main phases: next hop selection and channel selection. The routing is done hop-by-hop with local information and decisions, which are more compatible with sensor networks. Primary user action and prevention from interfering with them is considered in all spectrum decisions. It uniformly distributes frequency channels between neighboring nodes, which lead to a local reduction in collision probability. This clearly affects energy consumption in all sensor nodes. The route selection is energy-aware and a learning based technique is used to reduce the packet delay with respect to hop-count. The imitation reveals that by applying cognitive radio technology to WSNs and selecting a proper channel, we can consciously decrease collision probability. This saves energy of sensor nodes and improves the network lifetime.