Optimization of sensing time in multichannel sequential sensing for cognitive radio

This paper studies the design of sensing time in multichannel sequential sensing for cognitive radio under the multichannel sensing slots and one transmission slot scheme. Firstly, we consider the case where the channel idle probability is known. In this case, when the channels’ signal‐to‐noise ratios (SNRs) are equal, we prove that there exist optimal sensing times that maximize the achievable throughput for secondary user, while primary user is sufficiently protected. When the channels’ SNRs are different, brute‐force search is used to find the optimal sensing order that maximizes the achievable throughput of secondary user, and the corresponding optimal sensing times will be obtained. Then, a suboptimal and low‐complexity approach of one‐slot sensing time without knowing the channel idle probability is proposed. The proposed approach solves the problem of sensing order by selecting the channel with the minimum sensing time in the next sensing slot when the channels’ SNRs are different. Numerical results show that the proposed approach achieves a performance close to that of the optimal sensing time under different conditions and has significant performance improvement over the approach of fixed sensing time. Copyright © 2011 John Wiley & Sons, Ltd.