LTE-A系统中小区搜索算法研究

发布时间：2018-06-25 16:29

本文选题：长期演进 + 正交频分多址　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：LTE-A系统中,当用户设备在一个小区系统覆盖范围内开机时,为了接入到网络中,首先必须要对该用户设备附近基站所发送的下行链路中主同步信号(PSS)和辅同步信号(SSS)进行检测,这就是小区搜索过程。小区搜索完成之后就可以获得定时同步和载波频率偏移以及所在小区的ID。研究小区搜索算法就是为了提高小区ID检测的准确性,并且准确估计出载波频率偏移,或者尽量降低算法的复杂度,便于算法实现,使得用户设备能够准确快速的与基站取得同步并且接入到网络中。本文首先介绍LTE-A的研究状况,然后对LTE-A采用的MIMO、OFDM等技术以及LTE-A下行物理层进行概述,重点研究了LTE-A的帧结构以及PSS检测、SSS检测技术以及频偏估计算法。在PSS检测部分,介绍了传统的基于互相关的PSS检测算法以及差分互相关PSS检测算法,给出了一种检测性能优异的改进的分段互相关PSS检测算法。在SSS检测算法中,分析对比了传统的SSS信号相干检测和非相干检测算法,给出了一种性能更好且复杂度较低的新算法。在频偏估计部分,研究了OFDM系统基于CP的ML频偏估计算法,以及基于PSS信号检测结果,利用已知PSS本地信号的互相关估计算法,在此基础上给出一种改进的PSS互相关估计算法。仿真结果表明改进的PSS检测算法、新给出的SSS检测算法相对于原有算法,小区ID检测正确概率更高。改进的频偏估计算法相对于原有算法,估计值与精确值之间的MSE更低,估计值更加精确。
[Abstract]:In LTE-A system, in order to access the network, the main synchronous signal (PSS) and the secondary synchronous signal (SSS) in the downlink transmitted by the base station near the user equipment must be detected when the user equipment is turned on within the coverage of a cell system, and in order to access the network, the main synchronous signal (PSS) and the secondary synchronous signal (SSS) must be detected. This is the cell search process. After the cell search is completed, the timing synchronization and carrier frequency offset and the IDs of the cell can be obtained. Cell search algorithm is to improve the accuracy of cell ID detection, and accurately estimate carrier frequency offset, or reduce the complexity of the algorithm to facilitate the implementation of the algorithm. Enables user equipment to accurately and quickly synchronize with the base station and access to the network. This paper first introduces the research status of LTE-A, then summarizes the MIMO-OFDM techniques used in LTE-A and the LTE-A downlink physical layer, focusing on the LTE-A frame structure, PSS detection and frequency offset estimation algorithm. In the part of PSS detection, the traditional PSS detection algorithm based on cross-correlation and differential cross-correlation PSS detection algorithm are introduced, and an improved piecewise cross-correlation PSS detection algorithm with excellent detection performance is presented. In the SSS detection algorithm, the traditional SSS signal coherent detection and incoherent detection algorithms are analyzed and compared, and a new algorithm with better performance and lower complexity is proposed. In the part of frequency offset estimation, the ML frequency offset estimation algorithm based on CP in OFDM system is studied, and based on the detection results of PSS signal, an improved PSS cross-correlation estimation algorithm is proposed based on the cross-correlation estimation algorithm of known PSS local signals. Simulation results show that the improved PSS detection algorithm, the new SSS detection algorithm compared with the original algorithm, the cell ID detection is more accurate probability. Compared with the original algorithm, the MSE between the estimated value and the accurate value of the improved frequency offset estimation algorithm is lower and the estimation value is more accurate.
【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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