A low-complexity algorithm for utility based spectrum coordination in DSL systems

Abstract

The static resource allocation which is usually assumed for the DSL physical layer leaves unused a significant portion of the achievable rate region. An alternative approach is to divide time into slots of short duration, and to change the resource allocation from each time slot to the next. A crosslayer scheduler then chooses a different resource allocation setting for each time slot by defining a utility function for each user n, and solving the corresponding network utility maximization (NUM) problem. For spectrum coordination, this NUM problem is non-convex and solving it is NP-Hard. This paper therefore introduces a fast algorithm, referred to as NUM-DSB, which converges to a local solution of the NUM problem. NUM-DSB can be applied to any NUM problem, regardless of the considered utility functions's characteristics. Simulation results show that NUM-DSB can compete with the state of the art algorithm for smooth non-convex network utility maximization.