Heterogeneous torus quorum-based rendezvous in Cognitive Radio Ad Hoc Networks

Cognitive radio (CR) technology is the key technology that enables the Next Generation (xG) communication network, also called Dynamic Spectrum Access Networks (DSANs), to use spectrum in a dynamic manner. Due to the dynamic network topology and the time and location varying spectrum availability in Cognitive Radio Ad Hoc Networks (CRANs), there is a need of on-demand searching for a control traffic channel by CR 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 focus on RDV guarantee on all available common channels with the heterogeneous channel availability, while satisfying the heterogeneous Rotation Closure Property through complying with the heterogeneous difference (map) pair properties. We enhance a torus QS and Difference Set based rendezvous protocol, designed in our previous work, such that we can guarantee a small and bounded maximum Time-to-Rendezvous, and RDV on all channels in a hopping sequence period.