Equalizer training algorithms for multicarrier modulation systems

In a multicarrier data transmission system the length of a symbol is often limited by the maximum permissible delay of data from input to output. If the length of the impulse response of the channel is not negligible compared to the permitted symbol length, the impulse response can be shortened by passing the received signal through a time-domain equalizer before modulation. The best performance for a given computational complexity can then be achieved by appending to each block of samples of the transmit signal a cyclic prefix that has the same length as the shortened impulse response. Several algorithms for designing the time-domain equalizer, which use adaptation in the frequency domain and windowing in the time domain in order to minimize the mean squared error of the equalized response, are described