Interference-aware spectrum handover for cognitiveradio networks

Cognitive radio CR is a promising technique for future wireless networks, which significantly improves spectrum utilization. In CR networks, when the primary users PUs appear, the secondary users SUs have to switch to other available channels to avoid the interference to PUs. However, in the multi-SU scenario, it is still a challenging problem to make an optimal decision on spectrum handover because of the the accumulated interference constraint of PUs and SUs. In this paper, we propose an interference-aware spectrum handover scheme that aims to maximize the CR network capacity and minimize the spectrum handover overhead by coordinating SUs' handover decision optimally in the PU-SU coexisted CR networks. On the basis of the interference temperature model, the spectrum handover problem is formulated as a constrained optimization problem, which is in general a non-deterministic polynomial-time hard problem. To address the problem in a feasible way, we design a heuristic algorithm by using the technique of Branch and Bound. Finally, we combine our spectrum handover scheme with power control and give a convenient solution in a single-SU scenario. Experimental results show that our algorithm can improve the network performance efficiently.Copyright © 2012 John Wiley & Sons, Ltd.