Torus quorum system and difference set-based rendezvous in Cognitive Radio Ad Hoc Networks

In Cognitive Radio Ad Hoc Networks (CRANs) a frequently changing environment and Primary Users channel occupancy result in a need of the searching for a common control channel by Secondary Users in order to be able to initiate a communication. A rendezvous (RDV) is therefore a new challenge, not encountered in single channel networks. Hence, methods guaranteeing that all nodes meet periodically in reasonable periods of time should be advocated, i.e., instead of using pseudo-random solutions, systematic approaches should be considered, e.g, quorum systems (QSs) popular especially in power saving protocols. In this study, we propose a novel rendezvous protocol (tQS-DSrdv) which allows to form channel maps based on torus Quorum System (tQS) and difference set (DS) concepts. Thanks to the use of both concepts we are able to guarantee RDV on all r channels when a number of channels is small (r ≤ 4) and on r - 1 channels otherwise.