Research On Channel Estimation Technology In MIMO-OFDM System Based On Pilot

For the advantages of improving the channel capacity significantly and resisting the multi-path fading effectively, MIMO-OFDM has been a focus in the current communications field and regarded as the most potential link transmission technology in next generation mobile communication; channel estimation is a key and difficulty in MIMO-OFDM system, so the research of channel estimation has arose a lot of attention in wireless communications domain.Aiming at the performance of the channel estimation with different algorithms and pilot schemes in MIMO-OFDM system, LS algorithm and MMSE algorithm was compared, the estimation performance of LS algorithm and MMSE algorithm under the traditional one-dimension pilot in OFDM system and that of MMSE algorithm under two-dimension pilot in MIMO-OFDM at the pilot position. By researching of Gauss interpolation and Cubic interpolation, the estimation performance of complete channel response in MIMO-OFDM system based on interpolation was analyzed. Aiming at the complex computation of MMSE algorithm, a simplified SVD algorithm based on subcarrier grouping was proposed, this method can reduce the complexity of channel estimation computation significantly in the system and keep the good estimation performance of the former algorithm under the condition that the number of antennas and the subcarriers in the system were not limited.At last, aiming at the problem that the channel estimation performance should be improved and the complexity of the pilot estimation should be reduced, an improved pilot scheme based on space-frequency-MMSE was desinged. Compared with MMSE algorithm under two-dimension pilot, the improved scheme can improve the estimation performance further, at the same time the complexity of the algorithm and pilot is lower than that of MMSE algorithm under two-dimension pilot.