Patent ID: 7522877

Claim:
A method for reducing echo noise in satellite communications in which a hub communicates with multiple remote stations via a satellite having a nonlinear satellite transponder, the method comprising the steps of: transmitting a transmit signal from the hub to the multiple remote stations, where the transmit signal contains at least one carrier; providing, at the hub, a replica of the transmit signal to a buffer that provides an integer sample delay; distorting, at the hub, the replica of the transmit signal according to nonlinearities of the satellite transponder to provide a distorted replica of the transmit signal; determining, at the hub, a scaled, fractional-sample time-delayed, frequency-shifted, and attenuated version of the distorted replica of the transmit signal to provide a compensated distorted replica of the transmit signal; and using, at the hub, the compensated distorted replica to represent the nonlinearities of the satellite transponder and reduce echo noise from a received aggregate signal received by the hub from the multiple remote stations via the satellite transponder; wherein the distorting step further comprises applying a block conversion to the transmit signal to form the distorted replica occupying a predetermined frequency range and the determining step further comprises tracking the integer sample closest to a weight vector centroid of an adaptive filter to provide fractional-sample delay of the distorted replica.