Targeted rectangular conditioning

A vectoring controller for configuring a vectoring processor that jointly processes Discrete Multi-Tone DMT communication signals to be transmitted over or received from a plurality of N subscriber lines according to a vectoring matrix, the vectoring controller configured to, for given ones of a plurality of tones:

• enable the given tone for direct data communication over a first set of N−Mk targeted lines out of the N subscriber lines,
• disable the given tone for direct data communication over a second disjoint set of Mk supporting lines out of the N subscriber lines, Mk denoting a nonnull positive integer,
• configure the vectoring matrix to use, when transmitting, an available transmit power, and to use, when receiving, an available receive power, at the given tone over the second set of Mk supporting lines for enhancement of data signal gains at the given tone over the first set of N−Mk targeted lines,
• distribute targeted and supporting roles across the N subscriber lines while iterating through the plurality of tones in sequence such that respective data rates over the N subscriber lines are steered towards respective target data rates,
• during the respective iterations, update the respective data rates over the N subscriber lines based on the enabled and disabled tones and the configuration of the vectoring matrices during the respective iterations, and
• determine first and second sets of lines based on the updated data rates.