Method and apparatus for time-domain equalization in FDM-based discrete multi-tone modems

The present invention relates to a discrete multi-tone (DMT) modem. More particularly, the present invention relates to a method and apparatus for time-domain equalization in a frequency division multiplexing (FDM) based DMT modem to improve echo suppression, and reduce the effects of leakage of out of band frequency noise into in band signals. A time domain equalizer for a discrete multi-tone modem that includes an estimation of the contribution of out of band noise and echo to the overall channel impulse response. At start up the modem estimates out of band noise and echo. Using a minimum mean square error analysis, the time domain equalizer taps can be determined, taking into account the estimated out of band contribution. As a result, less complex duplexing filters, and time domain equalizer, are required.