Channel Estimation Techniques for MIMO-OFDM Systems Using Pilot Carries on Multipath Channels

In high capacity systems, as the bit transmission rate increases, Intersymbol Interference (ISI) caused by the multi-path channel reduces the system efficiency. The technique of OFDM acts very well against this phenomenon. On the other hand, an accurate estimation of the communication channel coefficients improves the performance of communication systems effectively. In this paper, the estimation algorithms of the MIMO-OFDM channel are investigated to compare them in terms of estimation error and calculation complexity. In the following, a method is proposed to improve the estimation of the MIMO-OFDM channel. In this method, combining the LS algorithm with adaptive algorithms improves the estimation performance at different Doppler frequencies. We observe in the simulations that the use of adaptive algorithms improves the estimation of the channel at Doppler frequencies.