An Estimation Algorithm of Time-Varying Channels in the OFDM Communication System

The orthogonal frequency division multiplexing (OFDM) has the advantages of a high spectrum utilization and anti-multipath interference, and can be used in a high-speed data transmission system of the wireless environment. In this paper, an algorithm of channel estimation is deduced based on the channel impulse response (CIR) model of the discrete time in a time-varying channel for the OFDM system. Considering that the normalized doppler shift is very small in the actual mobile communication, so this paper adopts the second-order taylor series expansion to approach the inter-carrier interference (ICI) to simplify the channel estimation model. Moreover, the discrete channel parameters are calculated by maximum likelihood estimation algorithms, and the root mean square error (RMSE) is analyzed by simulations. The improved algorithm can accurately estimate the parameters and improve the efficiency of the algorithm; in addition, the root mean square error and the convergence speed can get better performance.