基于SRS的LTE上行定时同步算法研究

发布时间：2018-11-27 09:12

【摘要】：3GPP组织于2004年提出了3G的长期演进(Long Term Evolution,即为LTE)计划,来满足人们对移动通信服务速率和服务质量的要求,保持3G的竞争力。LTE能够有效提高数据传输速率,降低系统时延,增大系统容量和覆盖范围,改善服务质量。因此,LTE技术将在未来的很长一段时间内成为通信的技术标准与发展方向,对LTE的研究工作具有重要的意义。本文主要是在FDD模式下基于探测参考信号(SRS)进行LTE上行链路的定时同步研究。首先,本文介绍了LTE技术的历史背景和国内外发展现状、性能要求和系统架构,对LTE技术物理层的有关概念进行了阐述,包括传输技术、数据帧结构、时频资源格、物理信道和参考信号。并重点介绍了SRS的生成映射方式和传送周期与位置。其次,本文在简要分析定时误差对接收信号的影响和LTE实现上行同步的过程之后,探讨了SRS信号在传输过程中的特点,然后重点研究了基于这种特点的参考序列的同步算法,包括经典的SC算法,以及在此基础上改进的Minn算法、Adegbenga B和Zhang算法。在AWGN信道下对这些算法性能仿真,观察各种算法的定时度量曲线,并比较它们的优点和缺点。结果表明,SC算法和Zhang算法由于平台的存在定时性能较差,Minn算法和Adegbenga B算法的定时性能较好,但是是以计算复杂度比较高为代价的。最后,本文介绍了LTE的仿真信道模型,然后给出了两种改进的基于SRS信号的定时同步算法。第一种改进算法是从时域的角度对SC算法的改进,第二种改进算法从频域的角度提取出接收信号相位中的定时信息。在单用户、两用户通信条件下,分别在AWGN信道和多径EVA信道中对这两种改进算法进行仿真,观察它们在各种通信条件下的性能。通过对这两种改进算法的仿真比较可以发现,SC改进算法在AWGN信道和多径EVA信道中定时性能更好,可以有效的抗噪和抗频偏;频域改进算法相比现有算法不仅定时性能得到改善,而且降低了计算复杂度。
[Abstract]:In 2004, 3GPP proposed the long-term evolution of 3G (Long Term Evolution, (LTE) program to meet the requirements of mobile communication service rate and quality of service, to maintain the competitiveness of 3G. LTE can effectively improve the data transmission rate. Reduce system delay, increase system capacity and coverage, improve quality of service. Therefore, LTE technology will become the technical standard and development direction of communication for a long time in the future, which is of great significance to the research of LTE. In this paper, the timing synchronization of LTE uplink based on probe reference signal (SRS) is studied in FDD mode. First of all, this paper introduces the historical background of LTE technology and its development status at home and abroad, performance requirements and system architecture, and describes the related concepts of the physical layer of LTE technology, including transmission technology, data frame structure, time-frequency resource lattice. Physical channels and reference signals. The generation and mapping mode of SRS and the transmission period and position are introduced in detail. Secondly, after analyzing the influence of timing error on received signal and the process of uplink synchronization by LTE, this paper discusses the characteristics of SRS signal in the transmission process, and then focuses on the synchronization algorithm of reference sequence based on this characteristic. Including the classical SC algorithm, as well as the improved Minn algorithm, Adegbenga B and Zhang algorithm. In the AWGN channel, the performance of these algorithms is simulated, the timing metric curves of various algorithms are observed, and their advantages and disadvantages are compared. The results show that the timing performance of SC algorithm and Zhang algorithm is poor due to the existence of the platform, and the timing performance of Minn algorithm and Adegbenga B algorithm is better, but at the cost of high computational complexity. Finally, this paper introduces the simulation channel model of LTE, and then gives two improved timing synchronization algorithms based on SRS signal. The first one is to improve the SC algorithm from the point of view of time domain, and the second is to extract the timing information from the frequency domain. The two improved algorithms are simulated in AWGN channel and multipath EVA channel under single-user and two-user communication conditions, and their performance under various communication conditions are observed. By comparing the two improved algorithms, it is found that the improved SC algorithm has better timing performance in AWGN channel and multipath EVA channel, and can effectively resist noise and frequency offset. The improved algorithm in frequency domain not only improves the timing performance but also reduces the computational complexity.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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