Cognitive wireless networks:key techniques and sate of the art

Key techniques in cognitive wireless networks and the state-of-the-art of this research were surveyed.The first focus was on the techniques to obtain network information,which was classified into spectrum sensing in PHY layer and available bandwidth estimation in network layer.Second,the design of multi-channel MAC protocols was introduced.In particular,both the characteristics and the applicable scenarios were analyzed for different types of multi-channel MAC protocols.Third,key techniques in the intelligent decision and the network reconfiguration were discussed.In the end,several suggestions on future research topics that should be put more effort in this field were given.