A Doppler Compensation Method for MIMO-OFDM Systems on Fading Channels

The paper proposes a Doppler compensation method for the MIMO-OFDM systems on fading channels. To deploy this method, we first propose a strategy to arrange the pilot symbols in the spatial domain, so that the orthogonality of subcarriers is maintained. Then, we develop a time synchronization method in the time domain, which uses both the correlation and the mean squared error function of the guard interval to improve the time synchronization performance. Finally, a novel Doppler compensation method is implemented in the frequency domain by using a non-uniform fast Fourier transform (FFT) matrix. The numerical simulations show that the proposed architecture provides a significant improvement in terms of system performance compared to the state of the art. At the same level of BER of $10^{-4}$, our system mechanism gains SNR of 2 dB in the case of using the FEC coding scheme. Without FEC coding, the gain of the SNR is above 1 dB in the same level of BER mentioned above.