Segment-Based Channel Assignment in Cognitive Radio Ad Hoc Networks

In the opportunistic spectrum sharing (OSS) paradigm, unlicensed users (a.k.a. secondary users) "opportunistically" operate in fallow licensed spectrum on a non-interference basis to licensed users (a.k.a. primary users). Each secondary user is equipped with a cognitive radio (CR) that has the capability to selectively operate in fallow licensed bands. In the OSS paradigm, the temporal and spatial spectrum variability caused by the primary users\´ spectrum utilization adds another dimension of complexity to the problem of channel assignment. Because existing channel assignment approaches (which were originally designed for conventional wireless networks)¿such as link-based and flow-based approaches¿do not consider spectrum variability, they do not offer the best trade-off in terms of complexity and performance. In this paper, we investigate the channel assignment problem In single radio Interface, CR ad hoc networks. We present a novel channel assignment scheme that assigns channels at the granularity of segments. The proposed scheme is significantly simpler than existing approaches, and offers several practical advantages. Using simulations results, we show that the proposed segment-based channel assignment strategy outperforms link-based channel assignment under realistic network conditions.