Optimum equalizer for OFDM systems with windowing

Addition of a postfix in orthogonal frequency division multiplexing (OFDM) symbol makes it possible to apply at the receiver a window different from the rectangular one and change the subcarrier spectrum. In doing so, inter-carrier interference (ICI) caused by frequency offset can be minimized. In this letter, we propose a minimum mean square error (MMSE) algorithm for the OFDM equalization which allows to utilize the energy invested into the postfix. As a result, the bit-error rate (BER) of an OFDM system can be improved.