Research on the New Channel Estimation Algorithm for MIMO-OFDM System Based on Training Sequence

Supporting high mobility will be an important character of the future wireless communication systems. It challenges the channel estimation technique a lot and there are two tough problems in front of us, they are multi-path fading channel and bandwidth efficiency. Orthogonal Frequency Division Multiplexing (OFDM) technique changed the frequency selective multi-path fading channel into flat fading channel in frequency domain which effectively mitigates the effects of multi-path propagation and, hence, increase data rate. In this paper, we discuss the principle of MIMO-OFDM systems based on the introduction of fading channels. Furthermore, the channel estimation technique in MIMO-OFDM system is investigated, with the emphasis on training-assisted channel estimation method. Firstly, we summarize and analyses the exiting channel estimation methods in MIMO-OFDM system. Secondly, we proposed a new channel estimation method for MIMO-OFDM system based on training sequence. A novel pilot pattern with higher frequency efficiency is established and we use a reasonable manner to insert pilot so that the system greatly reduced the training cycle, increased data rates. Finally, in order to track the time-varying channel, an improved direct decision method is further adopted. Theoretical analysis and numerical results show that the new channel estimation scheme can offer a good performance and a high ability to track the time-varying channel.