Patent ID: 8687497

Claim:
A vectored digital subscriber line (DSL) system, wherein the DSL system comprises: a vectoring group comprising an upstream-end DSL apparatus coupled to a plurality of downstream-end DSL modems; each downstream-end DSL modem configured to: receive data transmitted by the upstream-end DSL apparatus, wherein each downstream-end DSL modem is configured to collect error signal data sent using a downstream DSL frequency band, wherein the downstream DSL frequency band comprises a plurality of DSL frequency sub-bands, wherein each sub-band contains P DSL tones, further wherein the collected error signal data corresponding to error signals received for one base point DSL tone in each sub-band; and transmit collected error signal data to the upstream-end DSL apparatus; the upstream-end DSL apparatus comprising: one or more upstream-end DSL ports coupled to one or more of the downstream-end DSL modems; a vector processor (VPC) configured to: receive collected error signal data transmitted to the upstream-end apparatus by the plurality of downstream-end DSL modems; generate error-signal-based far-end crosstalk (FEXT) cancellation coefficient values for each base point DSL tone, wherein each error-signal-based FEXT cancellation coefficient value is calculated using the received error signal data; and generate approximated FEXT cancellation coefficient values for the (P-1) DSL tones other than the base point DSL tone in each sub-band, wherein the approximated FEXT cancellation coefficient values for each sub-band are calculated using the error-signal-based FEXT cancellation coefficient value for the base point DSL tone in that sub-band; and perform DSL vectoring for transmissions on DSL lines in the vectoring group using the generated error-signal-based FEXT cancellation coefficient values and the approximated FEXT cancellation coefficient values.