The Technology Of The Channel Estimation In The MIMO-OFDM System Based On IEEE802.11a WLAN

The object of this paper is to research the channel estimation technology of MIMO-OFDM system basing on IEEE802.11a. It introduces the estimation algorithms of single-antenna system, including training sequences, pilots estimation and LS estimation at the beginning. Then it proposes a new algorithm based on the iterative estimation. Simulations show that this method tracks the channel trait effectively.Aiming at the indoor environment and the burst transmission mode of WLAN system, this paper mainly introduces estimation algorithms of MIMO-OFDM system based on the training sequences. A frequency estimation method is first proposed and improved. Then basing on the LS estimation, the paper researches the best design methods of the training sequence including the orthogonal training and shift orthogonal training sequences. Through the simulation, we can prove the they are both best design methods, but shift orthogonal training sequence breaks through the limit of the number of transmit antennas and gets the least LS estimation MSE. Then a estimation algorithm to deal with worst multipath channel is proposed. Proved by simulation it can have the correct channel estimation even with the ISI.