Neighbor discovery based on group frequency hopping without common control channel for cognitive radio ad hoc networks

In traditional cognitive radio ad hoc networks (CRAHNs), each unlicensed node senses and attains its own idle frequency channel. Considering that the available channels at different nodes may be different, a dedicated common control channel (CCC) facilitates the exchange of the spectrum availability information of each node, and then forthcoming communication nodes tune to the same frequency channel and finish the communication. However, when CCC is unavailable, the problem of neighbor discovery becomes very challenging. In this paper, an asynchronous neighbor discovery algorithm based on group frequency hopping without CCC is proposed for CRAHNs, which is divided into preliminary discovery and further discovery. The former perceives the presence of the neighbor node and achieves a coarse discovery, while the latter makes the neighbor successfully meet to each other. Simulation results show that the proposed algorithm takes very little time to successfully discover the neighbor.