空地一体化网络频谱感知技术研究

发布时间：2018-01-07 16:05

本文关键词：空地一体化网络频谱感知技术研究　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着多媒体业务和高通量卫星技术的飞速发展,卫星宽带无线接入的需求正在急剧增长,目前卫星通信普遍采用时分复用,对频谱利用的研究较少。认知无线电(CR)技术可以有效地提高异构无线网络中的频谱利用率。但是如何在多个地面无线网络和卫星网络的混合网络中利用这一技术提高这类网络的频谱利用率是当前的研究热点。认知无线电技术允许认知用户和授权用户在同一频谱内共存而不影响授权用户的正常通信。频谱感知技术是认知无线电中的核心技术,但是过高的采样率严重制约了传统宽带频谱感知技术的发展。压缩感知能够克服传统宽带频谱感知对信号的采样速率必须满足奈奎斯特抽样定理,同时也是应用于空地一体化网络的关键技术。论文的研究工作得到了中国电子科技集团公司航天信息应用技术重点实验室开放基金项目的支持。针对上述热点问题,论文的主要工作如下:(1)提出了基于协作频谱感知的认知空地网络通信架构。首先研究了认知卫星动态接入空闲卫星授权频段以及地面授权频段的可行模式。针对未来宽带卫星中认知无线电技术的应用,本文提出了基于协作频谱感知的认知空地网络通信架构,使多个节点能够公平地接入卫星网络,同时满足了网络节点之间快速接入响应的需要,并详细分析了该架构的协作频谱感知运行模式以及功能框架,最后对多天线CR节点协作感知模型的性能进行了详细的分析。(2)提出了基于SGOMP的宽带压缩感知算法。针对正交匹配追踪(OMP)算法测量过程容易受到噪声干扰以及在实际应用中原始信号稀疏度可能不可用的问题,本文提出了一种称为随机梯度正交匹配追踪(SGOMP)的新型重建算法,随机梯度法用于替代正交匹配追踪(OMP)算法的最小二乘法,并在提出算法的基础上增加了提前终止条件,以减少算法复杂度。论文提出的认知空地网络通信架构降低了认知用户终端硬件设计复杂度,增加了系统噪声容限,显著提高了系统频谱利用率。仿真结果表明,所提出的算法在噪声环境下原始信号重构成功率较高。此外,使用提前终止阈值(ETT)可以在不影响算法重构成功率的前提下降低算法的复杂度。
[Abstract]:With the rapid development of multimedia services and high-throughput satellite technology, the demand of satellite broadband wireless access is growing rapidly. At present, time division multiplexing is widely used in satellite communication. Less research on spectrum utilization. Cognitive Radio (CR). However, how to improve the spectral efficiency of multiple terrestrial wireless networks and satellite networks by using this technology is the current research. Cognitive radio technology allows cognitive users and authorized users to coexist in the same spectrum without affecting the normal communication of authorized users. Spectrum sensing technology is the core technology in cognitive radio. However, the high sampling rate seriously restricts the development of traditional broadband spectrum sensing technology. Compressed sensing can overcome the traditional broadband spectrum sensing sampling rate of signals must meet Nyquist sampling theorem. At the same time, it is also the key technology applied in the air-ground integration network. The research work of this paper is supported by the open fund project of the key laboratory of aerospace information application technology of china electronic technology group corporation. In view of the above hot questions. Question. The main work of the thesis is as follows:. A cognitive air-to-ground network communication architecture based on cooperative spectrum sensing is proposed. Firstly, the feasible modes of cognitive satellite dynamic access to idle satellite authorization band and ground authorization band are studied. The application of wire-electric technology. In this paper, a cognitive air-to-ground network communication architecture based on cooperative spectrum sensing is proposed, which enables multiple nodes to access the satellite network equitably, and meets the need of fast access response between network nodes. The cooperative spectrum sensing mode and the functional framework of the architecture are analyzed in detail. Finally, the performance of multi-antenna CR node cooperative sensing model is analyzed in detail. (2) A wideband compression sensing algorithm based on SGOMP is proposed. The algorithm is prone to noise interference and the problem that the original signal sparsity may not be available in practical applications. In this paper, a new reconstruction algorithm called random gradient orthogonal matching tracking (SGOMP) is proposed, which is used to replace the least square method of orthogonal matching tracking (OMP) algorithm. In order to reduce the complexity of the algorithm, the proposed cognitive air-to-ground network communication architecture reduces the complexity of the hardware design of cognitive user terminal. The noise tolerance of the system is increased, and the spectrum efficiency of the system is improved significantly. The simulation results show that the proposed algorithm has a high success rate of original signal reconstruction in noisy environment. Using early termination threshold (ETT) can reduce the complexity of the algorithm without affecting the success rate of reconstruction.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925

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