Reliable Routing Technology In Cognitive Radio Ad Hoc Network

Cognitive radio technology has greatly enhanced spectrum efficiency and alleviated the problem of increasing scarcity of spectrum resources. These advantages led to its wide application in wireless communication systems, such as Ad Hoc networks which are flexible and invulnerable. As one of the key technology in the field of military, cognitive radio Ad Hoc network makes communications more intelligent by sensing and learning network environment. With the popularity of intelligent terminals and the development of the devices can be reconfigured, cognitive radio Ad Hoc networks have great application potential in the civil and commercial areas.It is the dynamic spectrum access feature of cognitive radio Ad Hoc networks that makes the available channels of nodes heterogeneous and time and location varying, that brings new challenges to cognitive radio Ad Hoc network routing. In this context, we study the reliable routing problem of cognitive radio Ad Hoc networks, focusing on dynamic spectrum access feature. We propose a routing protocol called SR-DSR, which can enhance the stability and reliability of data transmission in cognitive radio Ad Hoc networks.First of all, we introduce the research background and the basic concepts of cognitive Ad Hoc networks and confirm the research object in this paper. Then we describe the challenges of the routing study and issues that need attention in cognitive radio Ad Hoc networks, analysis of the current research in cognitive wireless network routing and further introduce several anti-jamming technologies which can be applied to the cognitive radio Ad Hoc networks.Based on the above theory and analysis, we present a reliable routing protocol(SR-DSR) in multi-interface and multi-channel cognitive radio Ad Hoc networks. In the proposed SR-DSR, by considering the complex radio and network environment and putting stability as a leading indicator, we select the route and channel jointly. According to the available channels of each node, SR-DSR formulates the path as a graph and calculates the Laplacian matrix of the graph to measure the stability of the path. In channel selection, SR-DSR takes into account the stability, the delivery ratio and capacity of the channel in an integrated way. In routing maintenance phase, SR-DSR maintains effective path by switching to the channel which is not affected by the jamming. Thus it reduces the influence of jamming. Simulation results in OPNET platform show that the proposed SR-DSR enhances the route reliability and stability compared with RASR and conventional DSR.Finally, the combination of SR-DSR and local reroute and multipath technology further optimize the routing protocol. Simulation results show that local rerouting has improved network performance by repairing routing failure caused by node movement locally. Thus it reduces the cost and delay of frequent reroute. Multipath routing provides a good solution for flow which has the requirement of delivery ratio.