Kalman-Filter Channel Estimator Based on Pilot Signal for WiMAX in Time and Frequency-Selective Fading Environment

A low-dimensional Kalman filter method is adopted in time and frequency-selective fading environment in Channel estimator based on block-type pilot signals for WiMAX which adopt OFDM physical layer. For simplicity, we use autoregressive process to model the time-varying channel. The algorithm take advantage the structure of OFDM symbol which has two-dimensional of time-frequency, first, the one-dimensional Kalman filter estimator is used to estimate per sub-carrier of channel; Then take least square algorithm to obtain the fading factor a. The second, a minimum mean-square-error combiner is used to refine one-dimensional Kalman estimates. The third step is to reduce high complexity of getting the inverse matrix utilizing the relationship of frequency response.