Patent ID: 8619843

Claim:
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.