Achieving k-channel-connectivity with topology control in cognitive radio networks

In view of the unpredictable activities of primary users (PUs), connectivity guarantee is of vital importance for the cognitive radio network (CRN). Existing works ensure the connectivity of the CRN with only one channel reclaimed by PU, without considering a general case that PUs occupy multiple channels simultaneously, thereby resulting in a network partition. In this paper, we aim at guaranteeing the k-channel-connectivity of the CRN, which refers to maintain the CRN's connectivity even when any k - 1 channels are requested by PUs at the same time. Particularly, we achieve the target by ensuring that any k - 1 independent sets (i.e., groups of SUs that transmit on the same channel) are not any vertex-cut set of the CRN. With that guidance, we firstly propose a topology control algorithm to minimize the number of channels required by the CRN, and to ensures that the topology remains k-channel-connected and conflict-free as well. Secondly, the correctness of the proposed algorithm is verified via theoretical analysis. Finally, extensive simulations are conducted to demonstrate the effectiveness of proposed algorithm. Simulation results show that our algorithm can not only enables the reductions of the required channels, but also the power consumption of the CRN.