Trading Off Rate and Power Consumption in DSL Systems

DSL systems have traditionally been tuned to maximize rate or margin, subject to constraints on transmitted power. Recently attention is focusing on reducing power consumption. We formulate a new DSL tuning framework in which the line driver power consumption is part of the objective function. The framework uses a model for line driver power consumption as a function of transmitted power, along with the traditional model for data rate as a function of transmitted power. Using this framework, we show that it is possible to achieve significant reductions in line driver power consumption while incurring modest reductions in data rate. To solve the resulting nonlinear problem efficiently, we propose a new heuristic algorithm based on the combination of linearization of the objective and subsequent linear programming techniques. Numerical studies illustrate the tradeoffs that are available in multi-line systems.