Investigation On Channel Estimation Based On Pilot Arrangement In MIMO-OFDM System

The requirements for the fourth generation (4G) wireless communication systems such as high data rate, high quality and high mobility make channel estimation techniques more challenging, while the complicated transmission environment gives rise to the difficulty of channel estimation. In this thesis, focus on channel estimation in MIMO-OFDM systems.This paper analyzed the fading character of the wireless channel and simulated the relationship of the user moving speed and accuracy in the channel estimation, researched the typical channel estimation methods. The principle of the MIMO-OFDM and channel estimation technique based on the pilot method was analyzed, the performance of the pilot method based on block-type and comb-type was simulated. The LS and MMSE algorithm based on STBC was emulated, the MMSE modified algorithm based on SVD is proposed, simulation results showed that the MSE and BER performance of the simplified algorithm is similar to the MMSE algorithm in literature[17], the complexity is lower. In addition, the iterative channel estimation algorithm based on expectation maximization (EM) algorithm is researched, an improved algorithm was proposed, simulation results showed that the algorithm guarantees performance while complexity is lower than the algorithm in literature[39].