Abstract: The present invention comprises a system and method for reduction of the influence of crosstalk, increase in and control over quality of service, increase in stability and reduction of power use in a system having multiple transmission lines. A novel crosstalk measurement method is introduced. Knowing the crosstalk, various algorithms may be employed, for example to reduce or eliminate its effects in order to guarantee a bit error rate equal to or less than the maximum allowed for each line. Similar methods are provided to minimize power consumption, or maximize related measures of line performance. Systems, devices, methods and techniques are provided that allow communication system to adapt transmission power margin, power spectral densities, and the like dynamically to changing subscriber's application needs in MIMO systems.