MIMO OFDM系统中同步和信道的联合估计

提出了一种MIMO OFDM系统的定时恢复、频率同步和信道估计的联合算法。为了减少算法的复杂度，算法分两步完成：首先利用接收信号的自相关函数进行粗同步和信道估计，得到时延和频偏的粗估计，然后在粗估计基础上采用最大似然准则进行精确的同步和信道估计。仿真结果表明，该算法能够达到很好的效果，系统误码率接近已知信道响应时的情况。

Joint estimation of synchronization and channel in MIMO OFDM

In this paper,a joint algorithm to estimate the symbol timing,carrier frequency offsets and channel estimation for multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing frequency(OFDM) is proposed.To reduce overall estimation complexity,the scheme is divided into two estimation stages.At the first stage,coarse timing and frequency estimates are obtained utilizing the autocorrelation function of the received signal.The timing offset and frequency offset were given by the coarse estimation.At the second stage,the fine timing and frequency offset estimates are obtained based on the maximum likelihood(ML) criterion.Then channel estimation for fine synchronization is performed.Simulations demonstrate that the coarse-to-fine method provides a good performance.The bit error rate(BER) is close to the BER in a case where the channel is known at the receiver.