Fast Neighbor Discovery with Lightweight Termination Detection in Heterogeneous Cognitive Radio Networks

An important step in the initialization of a wireless ad hoc network is neighbor discovery in which every node attempts to determine the set of nodes it can communicate with in one wireless hop. In recent years, cognitive radio technology has gained attention as an attractive approach to alleviate the congestion within the frequency spectrum. A cognitive radio transceiver can operate over a wide range of frequencies possibly spanning multiple frequency bands. A cognitive radio node can scan the frequency spectrum and dynamically identify frequencies that it can use for communication without interference from other wireless devices in its vicinity. When multiple cognitive radio nodes come together to form an ad hoc network, due to spatial variations in frequency usage and hardware variations in radio transceivers, different nodes in the network may perceive different subsets of frequencies available to them for communication. This heterogeneity in the available channel sets across the network increases the complexity of conducting neighbor discovery in a cognitive radio network. In this paper, we propose a new deterministic neighbor discovery algorithm for heterogeneous multi-hop cognitive radio networks with termination detection capability. Our algorithm allows nodes to detect termination of the neighbor discovery process. Our simulation results indicate that our algorithm is much faster compared to a recently proposed deterministic neighbor discovery algorithm (a reduction of 97-98% in time complexity ) and termination detection is lightweight (at most 3% of the total time complexity).