SUBSET: A joint design of channel selection and channel hopping for fast blind rendezvous in cognitive radio ad hoc networks

Without a common control channel in cognitive radio ad hoc networks (CRAHNs), two secondary users have to first hop on a common available channel before setting up their communication link. Existing papers on this blind rendezvous process mainly focus on the sequence design of channel hopping but do not consider the selection of available channels. Their time to rendezvous (TTR) and operation complexity increase with the number of available channels, which is against the concept that cognitive radios should perform better when there are more unused channels in primary networks. Thus, a new blind rendezvous design that can address this paradoxical issue is desirable. In this paper, we propose a joint design of channel selection and channel hopping for guaranteed blind rendezvous. For the first time, the TTR is significantly reduced to O(1) with a low operation requirement. An analytical model of TTR is also proposed and validated against the simulation. More importantly, under our proposed protocol, TTR decreases with the increasing number of available channels in the network. This is a very attractive feature in spectrum-under-utilized scenarios which has not been achieved by any existing CRAHN rendezvous work.