Abstract
Nowadays, in wireless communication system, the multiple input multiple output（MIMO）orthogonal frequency division multiplexing（OFDM）becomes a standard in wireless communications. The MIMO technique is delivering (Transmitter) and receiving (Receiver), both of them establish several antennae, it provides space time diversity, by promoting communication velocity or the exaltation wireless communication system data transmission quantity. OFDM technique has many advantages including high bandwidth efficiency and resist the effect of the multipath fading channel. Therefore the MIMO-OFDM technique has been the popular subject for many experts and scholars. Although OFDM has high bandwidth efficiency and resist to the multipath fading channel, OFDM is very sensitive about carrier frequency offset（CFO）and the phase shift. These phenomena may break the orthogonality between subcarriers and cause inter carrier interference （ICI）, destroy the bit error rate （BER）,and even cause the system breakdown. Many approaches about the CFO and channel response estimation for MIMO-OFDM systems have been proposed, but all of these algorithms require a priori knowledge about channel order（CO）. In [12], a technique can effectively solve this problem, but this technique complexity is very high. In this thesis, I propose a low complexity estimator which jointly estimates the CFO and channel response without a priori knowledge about channel order for a MIMO-OFDM systems. Imitate the identification through the computer, the method suggested, comparing to tradition, not knowing the channel order algorithm in advance, and it can achieve similar performance as the optimal estimator（ML）.