Routing Metric Design In Cognitive Radio Networks

Spectrum licensing has been a traditional approach to allocate the spectrum resources among different wireless communication systems. However, preliminary studies made by Federal Communications Commission (FCC) have indicated that many of the licensed spectrum bands are underutilized for a significant amount of time and at a large number of locations.Cognitive Radio (CR) is an emerging technology to significantly improve the spectrum utilization by taking use of the spectrum holes in time and space domains. The core idea of Cognitive Radio is to optimize the resource usage efficiency by sensing and learning the outside world and then, dynamically and adaptively reconfiguring its run-time parameters.Routing in Cognitive Radio is an edge-cutting and important research area. And routing metric design plays a key role in the routing research. From the perspective of inside the CR system, routing metric should capture the route end-to-end performance. While from the perspective of system coexistence between the Cognitive Radio networks and primary system, routing metric should also reflect the potential interference between the two systems.This paper intensively researched on the routing metric design in Cognitive Radio networks. Firstly, the background of Cognitive Radio and IEEE 802.22 was introduced; then, analyzed several typical routing metrics in multi-hop mesh networks; after that, the new feature of routing in Cognitive Radio networks was investigated and two kinds of routing metrics were proposed: 1) intra-system routing metric which aims to capture the end-to-end performance, and 2) inter-system performance which aims to reflect the interference between the primary and secondary systems; finally, intensive simulations were conducted and the proposed routing metrics were proved to well capture the route performance in the context of Cognitive Radio.