一种改进的MIMO-OFDM帧同步和载波频偏估计方法

在MIMO-OFDM系统中，每个接收天线上的信号都是多个发送天线信号的叠加，再加上多径的影响，使得帧同步比一般OFDM系统更加困难，为此提出了一种改进的用于MIMO-OFDM帧同步和载波频偏估计的正交帧头结构.通过在时域直接生成同步帧头，并在频域修正其频域特性，这种正交帧头能够区分每个发送天线到接收天线的不同到达时间，是通常的时域生成的正交帧头的改进，在保证时域正交性的同时，又具有良好的频域特性，有利于数字上变频.Matlab仿真结果表明，这种改进的帧头结构在帧同步和载波频偏估计中都有很好的性能.

Improved method for MIMO-OFDM frame synchronization and carrier frequency offset estimation

Frame synchronization in MIMO-OFDM(multi input multi output-orthogonal frequency division multipluxing) systems is more difficult than in OFDM systems because one receive antenna will get several waveforms from different transmit antennas.Furthermore,those waveforms will be degraded by multi-path delay.An improved preamble structure for MIMO-OFDM frame synchronization and carrier frequency offset estimation was presented.The orthogonal preamble for frame synchronization makes it possible that a receive antenna can distinguish the fine arriving time of different signals from different transmit antennas.The preamble is not only orthogonal in time domain,but also has a fine characteristic in frequency domain.Simulation results show that the preamble structure has good performance both in frame synchronization and carrier frequency offset estimation.