US 6,856,683 B1 · Method for reducing noise from a non-linear device that shares a customer loop with an asymmetric digital subscriber line modem

Abstract

A method for reducing noise from a non-linear device, such as a telephone, that shares a customer loop with a splitterless Asymmetric Digital Subscriber Line modem. The non-linearity of the device can cause some of the upstream signal to bleed into the downstream signal band. The modem examines the downstream band when it is transmitting fast retrain signals. By comparing the power in the band to a previous value when the modem transmitted upstream at a higher power level, the modem may determine whether to cut back its transmitted power to lessen the noise in the downstream band. In this manner, the method may allow optimal downstream data transfer regardless of what non-linear device shares the customer loop with the ADSL modem.

Claims17

Dependent claims

A method for reducing noise from a non-linear device that shares a customer loop with a splitterless Asymmetric Digital Subscriber Line modem, the method comprising the steps of:

measuring a current noise characteristic for the customer loop, wherein the current noise characteristic is measured by the modem, wherein measuring the current noise characteristic further comprises transmitting a plurality of tones from the modem to a central office over the customer loop, wherein the plurality of tones are Fast Retrain R-MEDLEY tones, and wherein the R-MEDLEY tones are repetitions of a thirty-eighth symbol of R-MEDLEY;
making a determination as to whether the current noise characteristic is within a comparison level of a previous noise characteristic;
and
when the determination is that the current noise characteristic is not within the comparison level of the previous noise characteristic, limiting transmitted power from the modem by an amount equal to a power cutback value, wherein limiting transmitted power comprises reducing power across transmit bins.

1 more element

Dependencies are inferred from the claim text.

Method for reducing noise from a non-linear device that shares a customer loop with an asymmetric digital subscriber line modem

Life of this patent

Method for reducing noise from a non-linear device that shares a customer loop with an asymmetric digital subscriber line modem

Life of this patent

Abstract

Claims17