LTE标准的MIMO-OFDM系统同步技术研究.pdf

摘要
当前，IEEE 、、3GPP LTE均已采用了OFDM和MIMO等关键
技术。从目前研究看来，OFDM/OFDMA、MIMO等技术将成为4G(4th Generation)
的主流技术。然而系统的时频同步与小区搜索的接入过程是任何OFDM蜂窝系统必
须解决的首要问题。本文的研究主要集中在多时延、多频偏的分布式MIMO-OFDM
系统定时与载波同步和LTE 系统小区初始搜索两个热点课题上。在分布式
MIMO-OFDM系统时频同步的研究中，为克服现有算法在多径衰落信道下定时性
能恶化的缺点，提出了两种基于不等周期反向共轭对称的定时同步改进算法，仿
真表明两种改进算法都具有良好的抗多径性能；同时，提出了一种适合多频偏估
计的算法，仿真表明其具有良好的估计性能。在LTE小区搜索的研究中，为了克服
传统ML算法相关峰不明显、现有Zadoff-Chu序列全相关算法对频偏敏感等问题，
提出了一种适合LTE系统突发传输的ZC部分相关联合MIMO最大比值合并的定时
同步改进算法，并进行了性能仿真比较表明其定时有效性；另外推导了LTE主同步
信号(Primary-SCH)在频域的一种自反特性，提出了一种新的整数倍频偏估计方法，
该方法具有良好的抗多径性能，并且实现简单；最后论文结合实际的物理层传输
控制机制，设计了一套完整的LTE系统小区初始搜索方案。

关键词： 分布式多输入多输出-正交频分复用(MIMO-OFDM) 定时同步
载波同步 长期演进 小区搜索
ABSTRACT
At present, OFDM and MIMO have been adopted by IEEE , , and
the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system.
From the present study, OFDM/OFDMA, it seems that MIMO technologies will
become mainstream technologies for 4th Generation (4G). However, the cell search
including time and frequency synchronization, and cell ID identification is one of the
most important issue that must be deal with for any OFDM cellular systems.
This paper focuses on two hot topics: timing and carrier synchronization for
distributed MIMO-OFDM system with multi-time delay and multi-frequency offset; and
cell initial search for LTE system. In the study of time and frequency synchronization
for distributed MIMO-OFDM system, in order to solve the problem of timing
perfermace deterioration of the existing algorithm in multipath-fading channel, two
improved symbol timing synchronization algorithms based on unequal period and
reverse conjugate symmetric synchronization pattern are proposed, and the simulation
results show that the proposed method offers an accurate estimation; and then a
multi-frequency offset estimation algorithm is presented, simulation results show its
good estimation performan