Enhanced Channel-Grouping Based Rendezvous Algorithm for Cognitive Radio Ad Hoc Networks

Rendezvous is a fundamental building block in Cognitive Radio Ad Hoc Networks (CRAHNs), in which pairs or groups of users must find a common available channel. In earlier researches, schemes based on common control channel (CCC) are widely used to achieve rendezvous, with the problems of control channel saturation, vulnerability to jamming attacks, and unsuitability for dynamic network scenarios. Therefore, the blind rendezvous based on Channel-Hopping (CH) sequences, which requires neither CCC nor the information of the target users’ available channels, has recently attracted a lot of research interests. As a contribution to this research area, Enhanced Channel-Grouping Based (ECGB) rendezvous algorithm is proposed for decentralized rendezvous. The ECGB algorithm has the following characteristics: 1) supporting both symmetric and asymmetric models; 2) full degree of rendezvous, i.e., any pair of cognitive users can rendezvous on any available channel; 3) guaranteeing rendezvous, with the upper bound of the maximum number of rendezvous slots under the asymmetric model, which is the quadratic function of the number of all channels; 4) requiring no time-synchronization. The upper bound of maximum TTR (MTTR) for the ECGB algorithm is derived by a theoretical analysis. Moreover, simulations confirm the theoretical derivation results of MTTR and show that the algorithm has a relatively short expected TTR (ETTR).