Role-Based Channel Hopping Algorithm for a Cognitive Radio Network in Asynchronous Environment

Cognitive radio network (CRN) has been recognized by researchers to solve the spectrum shortage problem, where the unlicensed users opportunistically exploit the idle licensed channels for data transmission. Prior to the data transmission, the SUs should rendezvous on an available idle licensed channel to establish a link or to exchange control information without causing interference to the co-located licensed channels. However, the dynamic behavior of channels and its availability make the rendezvous more challenging. A blind rendezvous on the available channels without any centralized unit, or a common control channel is preferable to address issues like long-time blocking, control channel saturation, and scalability in a congested network. In this paper, a blind rendezvous for a specific CRN is proposed, where a Role-Based Channel Hopping is introduced to achieve guaranteed rendezvous in an asynchronous environment. Analytical study shows that for N available channels, the maximum time to rendezvous is $$N+\lfloor \frac{N}{2}\rfloor$$ , degree of rendezvous is N, maximum conditional time to rendezvous is $$N^2$$ and Channel loading is $$\frac{1}{N}$$ .