An equalization method for OFDM in time varying multipath channels

An equalization method for OFDM systems in time varying multipath channels is investigated. Intercarrier interference (ICI) due to the Doppler spread in OFDM causes significant degradation of bit error rate (BER), which leads to an error floor. This influence becomes significant when the carrier frequency, moving speed of the receiver and OFDM block size increase. In order to cancel the ICI, the received OFDM symbol vector is equalized by multiplying the inverse matrix of the estimated channel matrix. The channel is modeled by a combination of multiple Doppler-shifted propagation paths and their equivalent parameters which are estimated by using specially scattered pilot symbols. Computer simulation results show that by using the proposed equalization method, the BER can be reduced significantly.