Method and apparatus for determination of vectoring matrices

A vectoring controller configured to determine a vectoring matrix that is used for joint processing of Discrete Multi-Tone DMT communication signals to be transmitted over, or received from, a plurality of subscriber lines, the vectoring controller being configured to determine first coefficient values for the vectoring matrix at a first tone based on a first number of iterations through an iterative update algorithm and based on a first channel matrix estimate at the first tone, and to determine second coefficient values for the vectoring matrix at a second neighboring tone based on a second number of iterations through the iterative update algorithm and based on a second channel matrix estimate at the second tone,

• wherein the vectoring controller is further configured to start with default coefficient values as initial values for the determination of the first coefficient values through the iterative update algorithm, and to start with the first coefficient values as initial values for the determination of the second coefficient values through the iterative update algorithm,
• and wherein the vectoring controller is further configured to set the second number of iterations to a value that is lower than the first number of iterations.