Optimal pilots in frequency domain for channel estimation in MIMO-OFDM systems in mobile wireless channels

In this paper, channel estimation schemes using pilot signals in the context of MIMO-OFDM systems are investigated. The proposed optimal training sequences can be inserted into every transmitter antenna pilot module synchronously, without vacancy, based on the MMSE principle. We can get more information about the mobile wireless channel, and the optimal pilot sequences derived in this paper outperform both the random and the existing orthogonal pilot sequences that appear to be suboptimal. Furthermore, the proposed method can work even when some transmitters or receivers are disabled, but the existing methods can not.