Dynamic Rate and Channel Selection in Cognitive Radio Systems
Dynamic Rate and Channel Selection in Cognitive Radio Systems
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DOI：
10.1109/jsac.2014.2361084
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发表时间：
2014-02
影响因子：
16.4
通讯作者：
Richard Combes;A. Proutière
中科院分区：
文献类型：
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作者：
Richard Combes;A. Proutière
在本文中，我们研究了认知无线电系统中的动态信道和速率选择，该系统利用了大量主用户空闲的信道。在这样的系统中，发射机可以迅速改变所选择的(信道、速率)对，以机会性地学习和跟踪提供最高吞吐量的对。我们将序贯信道和速率选择问题描述为一个在线优化问题，并证明了它与结构化多臂强盗问题的等价性。该结构源于所实现的吞吐量作为所选信道和速率的函数的固有属性。我们推导出任何信道和速率自适应算法所满足的基本性能限制，并提出达到(或接近)这些限制的算法。反过来，提出的算法最大限度地利用了吞吐量的内在结构。在静态和非静态无线电环境中，我们使用试验台和仿真实验来说明我们的算法的有效性。在静态环境中，在各种信道和速率对处的分组成功传输概率不会随时间而演变，而在非平稳环境中，它们可能会演变。在实际场景中，所提出的算法能够非常准确地跟踪最佳信道和速率，而不需要对各种信道的质量进行任何显式测量和反馈。
In this paper, we investigate dynamic channel and rate selection in cognitive radio systems that exploit a large number of channels free from primary users. In such systems, transmitters may rapidly change the selected (channel, rate) pair to opportunistically learn and track the pair offering the highest throughput. We formulate the problem of sequential channel and rate selection as an online optimization problem and show its equivalence to a structured multiarmed-bandit problem. The structure stems from inherent properties of the achieved throughput as a function of the selected channel and rate. We derive fundamental performance limits satisfied by any channel and rate adaptation algorithm and propose algorithms that achieve (or approach) these limits. In turn, the proposed algorithms optimally exploit the inherent structure of the throughput. We illustrate the efficiency of our algorithms using both test-bed and simulation experiments, in both stationary and nonstationary radio environments. In stationary environments, the packet successful transmission probabilities at the various channel and rate pairs do not evolve over time, whereas in nonstationary environments, they may evolve. In practical scenarios, the proposed algorithms are able to track the best channel and rate quite accurately without the need for any explicit measurement of and feedback on the quality of the various channels.