Multipath Routing Protocols in Cognitive Radio Networks

Current spectrum allocations are statically con-figured and cannot adopt network changes dynamically. The emerging field of Cognitive Radio Networks can be used to fulfil the current demand of spectrum by utilizing the vacant portion of spectrum opportunistically. Secondary users (cognitive users) can use spectrum whenever primary users (licensed users) are idle. Recent researches in the emerging field mainly focus on spectrum sensing and spectrum allocation that allow an opportunistic use of the vacant portions of the licensed frequency bands by the CR users. Efficiently use of channel information collected by secondary users is the most important in order to provide packet delivery timely in CR environment. In this paper, we are analysing the performance of both AODV and the routing scheme which utilizes multiple channels and multiple paths for routing purpose, we called "MultiChannel-MultiPath AODV. The effect of sensing time and transmitting time on both routing protocols are studied. Through various simulations in ns-2, we have analysed the improvement of routing scheme that utilizes multiple channels and paths over AODV (Ad-Hoc On-Demand Distance Vector) routing protocol. Packet delivery ratio, routing overhead and route discovery frequency (RREQ/sec) etc. are the metrics used for comparison. Finally, we have analysed the impact of primary user's arrivals and departures rate on secondary user's packet delivery ratio.