Patent ID: 6665308
Filing Date: 2003-12-16
Classification: H03M,H04B,H04H,H04J,H04L,H04N,H04W

Abstract:
A process for performing upstream equalization in a distributed digital data communication system having a central unit modem coupled to at least one remote unit modem by a transmission media, comprising:sending training data upstream from a remote unit modem transmitter to said central unit modem, said transmission occurring at any time said remote unit modem transmitter needs to perform training but times so as to arrive at said central unit modem during an interval reserved for ranging and training transmissions; receiving a downstream message from said central unit modem which is addressed to said remote unit modem which sent said training data upstream and which includes the actual equalization filter coefficients which have been set for tap coefficients of a digital upstream equalization filter in said central unit modem and which were derived by said central unit modem using an iterative adaption process to adapt said tap coefficients of said digital upstream equalization filter so as to equalize the data path from said remote unit modem which sent said training data to said central unit modem through said transmission media and convolving said equalization filter coefficients received from said central unit modem with existing tap coefficients of a digital precode filter in said remote unit modem transmitter and which was used to filter said upstream training data transmission said convolution resulting in new tap coefficients for said digital precode filter and setting said tap coefficients of said digital precode filter to the tap coefficients derived by said convolution calculation and using said digital precode filter for filtering further upstream payload data transmissions from said remote unit modem.