Bi-Channel-Connected Topology Control in Cognitive Radio Networks

In cognitive radio networks (CRNs), secondary users (SUs) must vacate the spectrum when it is reclaimed by the primary users (PUs). As such, multiple SUs that operate on the same channel requested by the PUs will be affected, resulting in a possible network partition. Therefore, how to maintain the connectivity of CRNs when PU appears is a critical problem. In this paper, we propose a topology control algorithm to address this problem. Particularly, we combine power control and channel assignment to construct a bi-channel-connected and conflict-free topology using minimum number of channels. Theoretical analysis shows that the CRN can maintain connectivity upon any single channel interruption by PUs. The simulation results demonstrate that the proposed algorithm can reduce the number of required channels efficiently and preserve energy spanner property.