Deterministic distributed rendezvous algorithms for multi-radio cognitive radio networks

Rendezvous is a fundamental process in constructing Cognitive Radio Networks (CRNs), through which the user can communicate with its neighbors by establishing a link on some licensed frequency band (channel). Most of the existing elegant rendezvous algorithms assume each user is equipped with a single radio. Nowadays the multi-radio cognitive radio architecture, where each user can access k ≥ 2 channels at the same time, has become a reality. In this paper, we study the rendezvous problem in multi-radio CRN to see whether and to what extent the multi-radio capability can improve the rendezvous performance. To begin with, we propose a family of deterministic distributed algorithms for two special situations when k=2 and k=O(√n), where n is the number of all channels. These algorithms show that the maximum time to rendezvous (MTTR) can be reduced (largely) in multi-radio CRN. Then we derive a lower bound of MTTR as Ω({|Vi||Vj|}/k2) for arbitrary k (Vi, Vj represents two users' available channel sets) and present a distributed algorithm to guarantee rendezvous in O({|Vi||Vj|}/k2) time slots, which meets the lower bound. Extensive simulations are conducted to corroborate our theoretical analyses.