Roteamento em Redes em Malha Hde R´ adios Cognitivos e IEEE 802.11

Cognitive radios are devices that access the unused portion s of licen- sed spectrum opportunistically. Therefore, depending on t he licensed radios ac- tivity, the cognitive devices may suffer from constant comm unication disruptions or even lack of opportunities in the access of the spectrum. T solve this pro- blem, we propose a new paradigm of interaction between 802.1 1 and cognitive radios to build hybrid mesh networks. In this proposed archi tecture every node has 802.11 interfaces, offering minimum spectrum access gu arantees, and some special nodes possess additional cognitive radio interfac es, which have larger transmission range that may be opportunistically used to cr eate cognitive short- cut links. Those shortcuts improve the hybrid network perfo rmance reducing the number of hops in routes and alleviating spectrum sharing in 802.11 channels. To enable those shortcuts, we propose a mechanism to discove r and select the best shortcuts in the routes of hybrid networks. Simulationresults show that this proposal performs well when compared to an optimal case.