Method to mitigate effects of ISDN off/on transitions in ADSL

摘要

The present invention provides for a method and apparatus for allocating data to subchannels used for ADSL transmission over a communication link which supports further system transmissions. An expected interference impact from the further system transmissions is estimated for the ADSL subchannels. Signal-to-noise ratios (SNRs) for the subchannels are determined for bit loading by an estimator (220). In one embodiment, actual noise associated with the communication link is used at initialization to determine a SNR which is subsequently modified by an adjusting unit (205) prior to bit loading responsive to the estimated interference impact. In another embodiment, a virtual noise signal, indicative of the estimated interference impact and generated by a noise signal generator (235), is summed with the actual noise prior to determining a SNR for bit loading. Prior to transmitting, the data is allocated to the subchannels by a bit loader (210) based on respective SNRs modified responsive the estimated interference impact.