Alien interference removal in vectored DSL
First Claim
1. A vectored digital subscriber line (DSL) system comprising:
- a plurality of active lines, wherein each active line comprises;
a downstream-end modem coupled to an upstream-end modem with a twisted copper pair;
wherein each active line is configured to use an upstream DSL frequency set to transmit upstream DSL user signals from the downstream-end modem to the upstream-end modem;
one or more pseudo signal source lines, wherein a pseudo signal comprises in-domain interference and correlated alien interference, each pseudo signal source line comprising at least one of the following;
an inactive line, wherein the inactive line comprises;
a twisted copper pair coupled to an upstream-end modem;
wherein no upstream DSL user signals are sent to the upstream-end modern using the upstream DSL frequency set;
a common-mode voltage signal source line comprising a twisted copper pair coupled to an upstream-end modem, wherein the upstream-end modem comprises;
an analog front-end comprising a hybrid configured to generate a common-mode voltage signal from transmissions on the common-mode voltage signal source line received by the upstream-end modem; and
a fast Fourier transform unit for generating pseudo signals derived from the generated common-mode voltage signals;
wherein the common-mode voltage signal source line is one of the following;
one of the plurality of active lines;
or a line other than one of the plurality of active lines;
a vectoring unit coupled to the upstream-end modems of the plurality of active lines and to the upstream-end modem of the inactive line, wherein the vectoring unit is configured to;
collect upstream DSL user signals received by the upstream-end modems of the plurality of active lines;
collect pseudo signals from one or more of the pseudo signal source lines;
remove the in-domain interference from the collected pseudo signals and generate alien interference data; and
perform vectoring of DSL transmissions on the plurality of active lines using the collected upstream DSL user data and the alien interference data.
6 Assignments
0 Petitions
Accused Products
Abstract
A vectored DSL system reduces or eliminates correlated alien interference in active DSL lines in the vectored system by collecting pseudo signals from inactive lines that do not carry upstream DSL transmissions and/or from common-mode voltage signals from active lines. The collected pseudo signals contain in-domain interference, such as FEXT interference from the active DSL lines in the vectored system, and correlated alien interference. After removing the in-domain interference from the pseudo signals, the remaining alien interference data can be used to generate FEXT cancellation coefficients or the like that are used in DSL vectoring to remove the correlated alien interference from upstream DSL user signals from the active DSL lines. The generated FEXT cancellation coefficients are used in a manner analogous to in-domain FEXT data collected from the active lines during training, tracking, etc. The vectored DSL system can include modems coupled to a private vectoring data routing apparatus to one or more vectoring modules The vectoring modules can employ vector processors that include processing units configured to process collected user data on the basis of all modems'"'"' data for a given DSL tone grouping, thus removing FEXT effects from the user data and returning vectored user data to the modems using the routing apparatus, which can be a specialized data transmission network utilizing one or more vector routers.
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Citations
14 Claims
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1. A vectored digital subscriber line (DSL) system comprising:
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a plurality of active lines, wherein each active line comprises; a downstream-end modem coupled to an upstream-end modem with a twisted copper pair; wherein each active line is configured to use an upstream DSL frequency set to transmit upstream DSL user signals from the downstream-end modem to the upstream-end modem; one or more pseudo signal source lines, wherein a pseudo signal comprises in-domain interference and correlated alien interference, each pseudo signal source line comprising at least one of the following; an inactive line, wherein the inactive line comprises; a twisted copper pair coupled to an upstream-end modem; wherein no upstream DSL user signals are sent to the upstream-end modern using the upstream DSL frequency set; a common-mode voltage signal source line comprising a twisted copper pair coupled to an upstream-end modem, wherein the upstream-end modem comprises; an analog front-end comprising a hybrid configured to generate a common-mode voltage signal from transmissions on the common-mode voltage signal source line received by the upstream-end modem; and a fast Fourier transform unit for generating pseudo signals derived from the generated common-mode voltage signals; wherein the common-mode voltage signal source line is one of the following;
one of the plurality of active lines;
or a line other than one of the plurality of active lines;a vectoring unit coupled to the upstream-end modems of the plurality of active lines and to the upstream-end modem of the inactive line, wherein the vectoring unit is configured to; collect upstream DSL user signals received by the upstream-end modems of the plurality of active lines; collect pseudo signals from one or more of the pseudo signal source lines; remove the in-domain interference from the collected pseudo signals and generate alien interference data; and perform vectoring of DSL transmissions on the plurality of active lines using the collected upstream DSL user data and the alien interference data. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for performing DSL vectoring in a DSL system having a plurality of active lines, the method comprising:
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transmitting test signal input signals on the plurality of active lines; collecting test signal output signals from the active lines; collecting pseudo signals comprising in-domain interference and correlated alien interference; removing in-domain interference from the collected pseudo signals to generate alien interference data; and performing DSL vectoring of the plurality of active lines using the alien interference data; wherein each active line comprises a downstream-end modem coupled to an upstream-end modem with a twisted copper pair, wherein each active line is configured to use an upstream DSL frequency set to transmit upstream DSL user signals from the downstream-end modem to the upstream-end modem; further wherein pseudo signals are collected from at least one of the following; one or more inactive DSL lines, wherein each inactive DSL line comprises a twisted copper pair coupled to an upstream-end modem, wherein no upstream DSL user signals are sent to the upstream-end modem using the upstream DSL frequency set; one or more common-mode voltage signal source lines, wherein each common-mode voltage signal source line comprises a twisted copper pair coupled to an upstream-end modem. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification