Adaptive Carrier Frequency Offset and Channel Estimation for MIMO-OFDM Systems
The issues of carrier frequency offset (CFO) and channel estimation are very important for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) wireless communication systems. In this paper, the problems of CFO and channel estimation are considered. An adaptive estimation algorithm is proposed. It can estimate CFO and channel parameters at the same time. Since the estimation method is real-time, it can work at a fast time-varying environment. However, the model becomes a huge nonlinear system if CFO and channel parameters are estimated simultaneously. It is a heavy load for the wireless communication system, even the extended Kalman filter can solve the nonlinear estimation. A multiple model, which includes many subchannel models, is constructed. The subchannel with CFO can be separately estimated. The accurate CFO is obtained by integrating estimated CFOs from subchannel models with weighting technology. The computational complexity can be reduced by this method. Finally, several simulations are given to prove the performance in comparison with other methods.