Routing in Hybrid Mesh Networks of Cognitive and IEEE 802.11 Radios

Cognitive radios (CRs) are devices that access spectrum opportunistically taking advantage of unused portions of licensed spectrum. Therefore, depending on the licensed radios activity, cognitive devices may suffer from constant communication disruptions or even lack of opportunities in the access of the spectrum. To solve this problem, we propose a new paradigm of interaction between 802.11 radios and CRs to build hybrid mesh networks. In this architecture every node has 802.11 interfaces, which offer minimum spectrum access guarantees, and some special nodes possess additional CR interfaces, which may be opportunistically used to create cognitive shortcut links. These shortcuts improve the hybrid network performance reducing the number of hops in routes and alleviating spectrum sharing in 802.11 channels. In order to create these shortcuts, we propose a shortcut discovering and selecting mechanism that presents a good performance when compared to an optimal case.