CROSSTALK MITIGATION FOR OUT-OF-BAND TONES

摘要

The present invention relates to a method for jointly processing Discrete Multi-Tone DMT communication signals making use of a common tone spacing and to be transmitted over, respectively received from, a plurality of subscriber lines (L 1 .. L 4 ). DMT communications over a first subset (L 1 , L 2 ) of the plurality of subscriber lines is confined within a first transmit spectrum (17a), and DMT communications over a second disjoint subset (L 3 , L 4 ) of the plurality of subscriber lines is confined within a second extended transmit spectrum (35b) that is a frequency extension of the first transmit spectrum. The method comprises inputting first groups of frequency samples (u i,K-k ) to be transmitted over, respectively received from, the first and second subsets of subscriber lines at respective first tones (K-k) and following a first group selection order, alternated with second mirrored groups of frequency samples (u i,K+k ) to be transmitted over, respectively received from, the second subset of subscriber lines at respective second mirrored tones (K+k) of the first tones, and following a second mirrored group selection order of the first group selection order, to a vectoring processor (120) for joint mitigation of first crosstalk present over the first and second subsets of subscriber lines at the respective first tones and second crosstalk present over the second subset of subscriber lines at the respective second tones. The first tones are common to the first and second transmit spectra. Mirroring is with respect to a folding frequency (K) derived from a reference sampling frequency applicable to the first subset of subscriber lines.