认知无线网络分布式主动频谱切换技术研究

发布时间：2019-05-11 10:55

【摘要】：在频谱利用中,可利用的频谱和性能较好的频谱,是有限的,并已有固定的分配,而对频谱的需求却在不断的增长。另一方面,现有频谱利用率并不是很高。因此,在认知无线网络中,授权用户不使用频谱时,即信道空闲时,认知用户在不影响授权用户性能的基础上,利用空闲频谱进行通信,来提高频谱的利用率。在基于感知信息不准确的分布式主动频谱切换算法中,认知用户之间不需要交互时钟同步和频谱切换信息,利用信道的三个状态来确定信道状态。利用虚警、漏检、错检概率对信道状态转移概率进行修正,纠正了感知信息不准确的情况,能够有效地提高认知用户对未来信道占用状况预测的准确性。通过此算法,选择出最优的信道进行通信,降低认知用户在频谱切换过程中的被动切换次数和冲突次数。与集中式主动频谱切换相比,也减少了计算复杂度等附加开销。在基于频谱聚合的分布式主动频谱切换算法中,通过感知整个频谱信道状态及信道状态转移概率矩阵,预测下一时隙信道各个状态的概率,选出最优的聚合区域及聚合区域内最优的满足频谱需求的信道,达到聚合区域被动切换次数最少的目标。同时,聚合区域主动切换次数、聚合区域总的切换次数、信道接入及通信过程中的冲突次数等性能都有较好的改进。本文的主要创新点:在分布式主动频谱切换条件下,不需要在认知用户之间交互时钟同步和频谱切换信息,通过将信道状态由原先的两个状态变为三个状态,加入了对其他认知用户的感知。不仅考虑了认知用户和授权用户之间的冲突,也考虑了认知用户之间的冲突。同时利用感知信道错误概率对信道状态转移概率进行修正,纠正了感知信息不准确的情况。在此模型的基础上,我们提出了两种算法:基于感知信息不准确的分布式主动频谱切换算法和基于频谱聚合技术的分布式主动频谱切换算法。
[Abstract]:In spectrum utilization, the available spectrum and the spectrum with good performance are limited and have fixed allocation, but the demand for spectrum is increasing. On the other hand, the existing spectrum efficiency is not very high. Therefore, in cognitive wireless networks, when authorized users do not use spectrum, that is, when the channel is idle, cognitive users use idle spectrum to communicate without affecting the performance of authorized users to improve the utilization of spectrum. In the distributed active spectrum switching algorithm based on inaccurate perceptual information, the interactive clock synchronization and spectrum switching information are not needed between cognitive users, and the three states of the channel are used to determine the channel state. The false alarm, missed detection and error detection probability are used to correct the channel state transition probability, which corrects the inaccurate perceptual information and can effectively improve the accuracy of cognitive users' prediction of channel occupation in the future. Through this algorithm, the optimal channel is selected to communicate, and the passive switching times and collision times of cognitive users in the process of spectrum switching are reduced. Compared with centralized active spectrum switching, it also reduces the additional overhead such as computational complexity. In the distributed active spectrum switching algorithm based on spectrum aggregation, the probability of each state of the next slot channel is predicted by sensing the whole spectrum channel state and the channel state transition probability matrix. The optimal aggregation region and the optimal channel to meet the spectrum requirements in the aggregation region are selected to achieve the goal of minimum passive switching times in the aggregation region. At the same time, the performance of active switching times in aggregation area, total switching times in aggregation area, conflict times in channel access and communication process has been improved. The main innovation of this paper is that under the condition of distributed active spectrum switching, there is no need for interactive clock synchronization and spectrum switching information between cognitive users, by changing the channel state from the original two states to three states. A perception of other cognitive users has been added. Not only the conflict between cognitive users and authorized users is considered, but also the conflict between cognitive users is considered. At the same time, the channel state transition probability is corrected by using the perceived channel error probability, and the inaccurate perceptual information is corrected. On the basis of this model, we propose two algorithms: distributed active spectrum switching algorithm based on inaccurate perceptual information and distributed active spectrum switching algorithm based on spectrum aggregation technology.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN925

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