A group-theoretic framework for rendezvous in heterogeneous cognitive radio networks

Abstract

In cognitive radio (CR) networks, a pair of CR nodes have to ``rendezvous'' on a common channel for link establishment. Channel hopping (CH) protocols have been proposed for creating rendezvous over multiple channels to reduce the possibility of rendezvous failures caused by the detection of primary user signals. Rendezvous within a minimal bounded time over multiple channels is a challenging problem in heterogeneous CR networks where two CR nodes may have asynchronous clocks, different sensing capabilities, no common universal channel set, and heterogeneous channel index systems. In this paper, we present a systematic approach using group theory for designing CH protocols that guarantee the maximum number of rendezvous channels and the minimal time-to-rendezvous (TTR) in heterogeneous environments. We derive the minimum upper bound of TTR, and propose two types of rendezvous protocols that are independent of environmental heterogeneity. Analytical and simulation results show that these protocols are resistant to rendezvous failures under various network conditions.