A Hybrid Cognitive Radio System: A Combination of Underlay and Overlay Approaches
A Hybrid Cognitive Radio System: A Combination of Underlay and Overlay Approaches
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DOI：
10.1109/vetecf.2010.5594302
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发表时间：
2010-10
期刊：
影响因子：
--
通讯作者：
J. Oh;Wan Choi
中科院分区：
文献类型：
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作者：
J. Oh;Wan Choi
提出了一种混合认知无线电(CR)系统，其中结合了底层和覆盖认知无线电方法。偶尔从覆盖CR模式切换到底层CR模式能够最大化辅助(未授权)网络的平均吞吐量和辅助用户的稳定传输。通过在概率意义上控制从覆盖CR模式到下层CR模式的切换，在保持主(许可)用户的目标离线率的同时最大化了二次用户的吞吐量。由于混合方法中的主用户可能遭受附加干扰，因此对于给定的切换速率，推导出覆盖模式中的次用户的最佳发射功率。我们的分析和数值结果表明，所提出的混合认知无线电系统在最大化吞吐量和保持队列的稳定性方面具有优势。
This paper proposes a hybrid cognitive radio (CR) system where underlay and overlay CR approaches are combined. Occasional switches from an overlay CR mode to an underlay CR mode enable to maximize the average throughput of a secondary (unlicensed) network and stable transmission of a secondary user. By controlling switching from an overlay CR mode to an underlay CR mode in a probabilistic sense, the throughput of a secondary user is maximized while the target departure rate of a primary (licensed) user is retained. Since a primary user in a hybrid approach is likely to suffer from additional interference, optimal transmit power of a secondary user in an overlay mode is derived for given switching rate. Our analysis and numerical results show that the proposed hybrid CR system takes benefits in maximizing throughput and maintaining stability of a queue.