Cooperative spectrum sensing with imperfect feedback channel in the cognitive radio systems
Cooperative spectrum sensing with imperfect feedback channel in the cognitive radio systems
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DOI：
10.1002/dac.1129
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发表时间：
2010
影响因子：
2.1
通讯作者：
D.-C. Oh;Yong-Hwan Lee
中科院分区：
文献类型：
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作者：
D.-C. Oh;Yong-Hwan Lee
认知无线电的主要目标是提高频谱效率，同时对使用频谱的主要用户造成有限的干扰。因此，认知无线电的一个重要部分是频谱感知，它确定特定频谱是否被主用户占用。然而，由于无线信道的遮蔽和多径衰落，仅本地次用户的感测决策可能不够可靠。最近，协作频谱感知作为局部感知问题的补救措施而出现。为了以协作方式感知频谱，次要用户通过受到衰落和阴影影响的反馈信道向认知基站报告其本地决策。因此，虽然准确地获得了本地感知结果，但由于反馈误差，可能不适合做出协作决策。为了缓解这个问题，我们提出了一种基于硬决策组合的协作频谱感知方案，以应对因不完善的信道条件引起的反馈误差。在所提出的方案中，仅允许最有利的次要用户（那些报告信道条件为峰值的次要用户）进行合作。通过所提出的方案，我们可以最大化检测概率，同时保证维持所需的误报概率。仿真结果表明，该方案比传统方案提供了更好的频谱感知性能。版权所有 © 2010 约翰威利父子有限公司
The primary object of cognitive radio is to increase spectral efficiency, while causing limited interference to primary users who are using the spectrum. Hence, an essential part of cognitive radio is a spectrum sensing that determines whether a particular spectrum is occupied or not by a primary user. However, the sensing decision of a local secondary user alone may not be reliable enough due to shadowing and multipath fading of wireless channels. Recently, cooperative spectrum sensing has emerged as a remedy to the problems of local sensing. To sense the spectrum in a cooperative manner, secondary users report their local decisions to a cognitive base station through a feedback channel that is subject to fading and shadowing. Therefore, though the local sensing result is obtained accurately, it might not be suitable for making a cooperative decision due to feedback error. To alleviate this problem, we propose a hard decision combining‐based cooperative spectrum sensing scheme in the presence of a feedback error caused by imperfect channel condition. In the proposed scheme, only the most favorable secondary users, those whose reporting channel conditions are peak, are allowed for cooperation. Through the proposed scheme, we can maximize the detection probability while guaranteeing that the desired false alarm probability is maintained. The simulation results show that the proposed scheme provides better spectrum sensing performance than the conventional scheme. Copyright © 2010 John Wiley & Sons, Ltd.