基于FPGA的认知无线电频谱感知的实时谱图的研究与实现

发布时间：2019-04-21 13:13

【摘要】：认知无线电技术为解决频谱资源的紧张状况提供了方法,它的核心内容是频谱感知技术,通过感知周围频段内频谱使用情况,找出频域空洞,为需要通信的用户进行合理的频段分配。实时谱分析通常被用来对各种突发信号进行侦查、捕获、分析,本文利用能量检测算法,对0MHz到1250MHz的宽带范围进行基于频谱感知的实时谱分析的研究与实现。本文主要分为以下三部分:首先,对频谱感知技术进行介绍,分析了不同方法的优缺点,结合0MHz到1250MHz的宽带内,对信号进行盲检测的要求,选择了基于噪声估计能量检测的算法进行研究与仿真分析。其次,对参数估计中的带宽估计、载频估计和符号速率估计进行了详细研究。其中带宽估计重点研究了基于Welch变换的算法;载频估计研究了频率居中法、M次方谱法,符号速率估计研究了瞬时幅度谱法、小波分析法和M次方谱法。在这些研究的基础上进行了仿真分析,通过充分比较各种方法的性能与实现难度,在基于FPGA的硬件实现中,对带宽估计选择了直接法,对载频估计和符号速率估计选择了M次方谱法。最后,实现了采样率最高可达5GHz的高速采样。根据硬件实现要求,选择使用多相滤波器组的方法,在XILINX-VC707评估板上完成了能量检测频谱感知基带系统的设计。通过Modelsim仿真,验证了基带系统每个模块功能的正确性。基带系统将检测的信号进行存储并导入电脑,在电脑上对信号进行实时频谱分析,画出信号的实时频谱图。
[Abstract]:Cognitive radio technology provides a way to solve the shortage of spectrum resources, its core content is spectrum sensing technology, by sensing the use of the spectrum in the surrounding frequency band, to find out the frequency domain hole. Reasonable frequency band allocation for users in need of communication. Real-time spectrum analysis is usually used to detect, capture and analyze all kinds of burst signals. In this paper, the real-time spectrum analysis based on spectrum sensing for the broadband range from 0MHz to 1250MHz is studied and realized by using the energy detection algorithm. This paper is divided into the following three parts: first of all, the spectrum sensing technology is introduced, the advantages and disadvantages of different methods are analyzed, and the requirements of blind signal detection are combined with the broadband 0MHz to 1250MHz. The algorithm based on noise estimation energy detection is selected for research and simulation analysis. Secondly, the bandwidth estimation, carrier frequency estimation and symbol rate estimation in parameter estimation are studied in detail. Among them, bandwidth estimation focuses on Welch transform, carrier frequency estimation, frequency centering, M-power spectrum, symbol rate estimation, instantaneous amplitude spectrum, wavelet analysis and M-power spectrum. On the basis of these studies, simulation analysis is carried out. By fully comparing the performance and implementation difficulty of various methods, in the hardware implementation based on FPGA, the direct method for bandwidth estimation is chosen. M-power spectrum is selected for carrier frequency estimation and symbol rate estimation. Finally, the high-speed sampling with the highest sampling rate up to 5GHz is realized. According to the requirements of hardware implementation, the method of using polyphase filter banks is selected to complete the design of the energy sensing spectrum sensing baseband system on the XILINX-VC707 evaluation board. The function of each module of baseband system is verified by Modelsim simulation. In the baseband system, the detected signals are stored and imported into the computer. The real-time spectrum analysis of the signals is carried out on the computer, and the real-time spectrum map of the signals is drawn.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925;TN791

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