Patent ID: 8830812

Claim:
A method, comprising: transmitting data to at least a first communication network device via at least a first communication line during a sequence of periods; for each period of the sequence of periods, receiving a separate value, each value being an average of measurements at the communication network device of measures of crosstalk of a plurality of communication network signal subcarriers, wherein each signal subcarrier of the plurality of signal subcarriers is associated with a corresponding matrix of a plurality of matrices; and for each individual signal subcarrier of the plurality of signal subcarriers, updating the matrix for the individual signal subcarrier based on the received values, the matrix for the individual signal subcarrier being configured to precode data transmissions to the communication network device over the individual signal subcarrier; wherein updating the matrix comprises: for a given one of the plurality of signal subcarriers, selecting one or more matrix elements to be updated in a manner configured to increase the value of the measure of crosstalk that is geometrically averaged over the plurality of signal subcarriers; for the given signal subcarrier, determining an estimate of the measure of crosstalk based at least in part on the geometrically averaged measure of crosstalk; for the given signal subcarrier, adjusting the matrix for precoding data transmissions for the selected matrix elements; and keeping respective matrices for precoding data transmissions for a remainder of the plurality of signal subcarriers other than the given subcarrier fixed.