【作者】 杨志伟；

【导师】 杨家玮； 刘勤；

【作者基本信息】 西安电子科技大学 ， 移动通信， 2007， 硕士

【摘要】 本论文来源于863计划课题“认知无线电技术研究”。认知无线电是一种智能的无线通信系统,它能够认知周围环境、通过“学习–创造”的方法相应地改变某些工作参数来实时地适应环境,从而达到提高频谱利用率、缓解频谱资源紧张的目的。本文主要研究了认知无线电中的环境感知及频谱探测技术。其中,提出的干扰温度估计的改进算法保留了多窗谱估计的准确度和近最优性特点,并大大减小了运算量,保证了实时性,同时还能够得到干扰温度和功率谱之间的准确对应关系。提出的动态频谱空洞探测方法在保证认知用户频谱要求的情况下,能够随着干扰温度估计值的变化而自适应调整频谱分辨率,从而具有较佳的分辨率与复杂度性能。最后,本文对GSM频段和WLAN频段的采集信号进行了频谱空洞探测和分析,验证了即使在使用频繁的频段中,仍然存在大量未使用频谱空洞。这就为认知无线电技术研究奠定了坚实的基础。更多还原

【Abstract】 The thesis comes from the National High-tech Research and Development Program (863 Program): the research of cognitive radio technique. With the rapid development of wireless communication, the finite spectral resource becomes more lacking in the fixed assignation mode, in which the utilization percent of spectral resource is low. Cognitive radio is defined as an intelligent wireless communication system that is aware of its surrounding environment and uses the methodology of understanding-by-building to learn from the environment and adapt its internal states by making corresponding changes in certain operating parameters in real time, in order to promote the efficient use of the spectrum and revive the lack of spectral resource.As one part of the 863 Program, the thesis mainly researches the techniques of wireless environment cognition and detection of spectrum holes in cognitive radio. The improved method of the interference temperature estimation holds multitaper method’s accuracy and near-optimality, and substitutes the relation between matrix singular value and matrix element for SVD in order to reduce its operations, improve its performance of real time and get the accurate relation between interference temperature and power spectrum. In another task, the dynamic detection method of spectrum holes could auto-adaptively change operating parameters based on strict interference temperature limit initialized by the cognitive radio services. The method could auto-adaptively changes spectral resolution by the changes of interference temperature estimate values, thus is provided with better spectral resolution and complexity performance. At the last part, the detection and analysis of spectrum holes in GSM and WLAN frequency bands is measured in order to validate that many waste spectrum holes exist even in the frequently occupied channels. The measure establishes a stable base for the cognitive radio research.更多还原