Abstract: In the channel estimation algorithm of MIMO-OFDM system, the least sctuares method (LS) based on frequcncy domain, has the very low implementation complexity under the guarantee of certain error performance, but its crror performance isn't best. After comparing many pilot symbol assisted algorithms, we designed a new pilot structure embarked from arbitrary receiving antenna,which can improve the channel estimation performance and reduce the compute complexity. In the new pilot structure, the sequences of pilot phase arc mutually orthogonal and evenly distributed.In addition, being different from the existing result that the pilot matrix adopts the shape of real part and imaginary unit, the clement of the proposed pilot matrix in this paper is real number or purely imaginary number so as to reduce the compute complexity effectively. The theoretical derivation proves that the proposed structure is the best pilot and has the minimum mean square error (MSE). The simulation results show that the proposed algorithm is better than the traditional method of least squares in mean square error, which is more obvious with the increase of signal to noise ratio(SNR). The proposed algorithm has the very low system error rate (SER) than the traditional least square, and muchbetter performance with increasing the number of sulrcarriers in the case of big SNR.

Key words: MIMO-OFDM, Pilot symbol assisted, Channel estimation, Wireless channel