Taxonomy and challenges of rendezvous algorithms in cognitive radio networks

Cognitive radio network (CRN) is a new networking paradigm in which unlicensed users with cognitive radios can opportunistically access idle channels in the spectrum of licensed users without causing interference. Rendezvous is a fundamental and essential operation for unlicensed users to meet and establish a communication link on a common channel, so that information exchange and data communication can be carried out. This article presents a comprehensive review of existing rendezvous algorithms and a possible taxonomy. We focus on the most representative rendezvous algorithms and summarize their characteristics. The article further highlights research directions of future study on rendezvous.