Applying The Balanced Capacity Concept to DSL Systems

This paper investigates a fair resource allocation method in crosstalk limited DSL (digital subscriber line) systems. As a measure of fairness, the concept of balanced capacity (BC), introduced in T. Sartenaer et al. (2005), is used. BC corresponds to a point on the boundary of the capacity region where each user experiences the same relative loss with respect to his maximum capacity. This is especially useful in near-far situations where some users can experience a huge capacity loss if the allocation is performed according to the sum-rate criterion (or any similar criterion). Our goal is to propose efficient algorithms to compute the BC point in DSL systems for constraints on individual power spectrum densities. Results are reported for typical crosstalk limited cases and are compared to a resource allocation optimized for the sum rate. The proposed algorithm is shown to be of low complexity.