MIMO-OFDM系统同步技术研究进展

多输入多输出正交频分复用（MIMO-OFDM）系统对定时偏移和频率偏差极其敏感，并且对时间同步精度要求极高。分析比较了29种具有代表性的MIMO-OFDM系统同步算法的优缺点,指出针对数据辅助类的同步方法，采用共轭、取反等特性构造优良正交性的训练序列是提高时间同步性能的关键，可在时域进行频偏估计和降低参数维数来降低系统计算复杂度；针对非数据辅助类的同步方法，构造计算复杂度较低的代价函数是提高频率同步性能的关键，这些都是MIMO-OFDM系统同步方法值得研究的方向。

Research progress on synchronization technology for MIMO-OFDM system

Very sensitive to timing offset and frequency offset, the Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) system requires high accuracy of synchronization.This paper analyzes and compares the advantages and disadvantages of twenty-nine representative synchronization algorithms for MIMO-OFDM system. On this base, it points out that, for data-aided synchronization method, the key to improve the time synchronization performance is to construct training sequences with good orthogonality on the basis of the characteristics of conjugate anti-symmetry,and the computational complexity of system can be lowered by conducting frequency offset estimation in time domain and reducing dimension parameters;for non-data-aided synchronization method, the key to improve the frequency synchronization performance is to construct cost function with lower computational complexity.The summarized techniques for MIMO-OFDM system deserve further investigation.