Abstract:

Cognitive radios have been envisioned as a chief technique for alleviating the severe shortage of available spectrum as well as improving the efficiency in using licensed spectrum in next generation communicating networks.Cognitive Radio Users (CRUs) coexist with Licensed Users through dynamically accessing licensed spectrum when it is idle.Before communication,it is vital for CRUs in asynchronous Cognitive Radio Networks (CRNs) to accomplish rendezvous and channel negotiation.We review recent studies on rendezvous schemes based on channel hopping sequences, analyze three classes of these schemes and conduct Matlab simulations to evaluate the performance of eight specific algorithms in terms of ETTR,MTTR and Fairness,concluding their respective merits and demerits.

Key words: cognitive radio;rendezvous;channel hopping sequence;TTR;fairness