Research of MMSE and LS channel estimation in OFDM systems

Orthogonal Frequency Division Multiplexing (OFDM) technique has received a lot of interest in mobile communication research lately. For wideband mobile communication systems, the radio channel is usually frequency selective and time variant. Hereafter, in OFDM systems, the channel transfer function of radio channel appears unequal in both frequency and time domains. Therefore, a dynamic estimation of the channel is necessary for the demodulation of OFDM signals. The channel estimation methods for OFDM systems based on pilot-aided are investigated. In view of the contradiction of LS and MMSE estimators between performance and computational complexity, two simplified estimator for LS and MMSE were presented. The simulation results show that the LS estimator algorithm has preferable performance and lower complexity. The simulation results also show that comparing to the LS channel estimation algorithm, the MMSE estimate of pilot signals algorithm provides better performance and requires reduce the computations.