A Novel Reduced Sensing Time Routing Protocol in Cognitive Radio Networks

Abstract

To avoid interference with primary users’ transmission in cognitive radio networks, the secondary users must perform a periodic spectrum sensing. The secondary users may cooperate with each other for sensing, in order to enhance the accuracy and reduce the overall spectrum sensing time. Spectrum sensing is also needed in other cognitive radio functions, such as in routing. Specifically, a cognitive radio node will not be able to route a packet to another cognitive radio node except if the channel is available on both nodes, where channels availability is determined by sensing. In this paper, a novel cooperative spectrum sensing protocol in ad-hoc cognitive radio networks is proposed in order to enhance routing performance. This approach is called Reduced Sensing Time Routing Protocol, in which a multi-hop path is found from a source to a destination. The route is composed of the intermediate cognitive radio nodes and the channel to be used at each hop. During the route setup phase, each intermediate node along the investigated path may select a neighbor node to perform channel sensing on its behalf, and this saved sensing time can be utilized to prolong the transmission time. As a result, the total end-to-end delay over the selected route is reduced. Simulation results show about 10% reduction in the overall average end-to-end delay as compared to conventional approach which assumes no cooperation exists in sensing between cognitive radio nodes.