Comparative simulation study of fast heuristics for power control in copper broadband networks

Abstract

The data-rate in currently deployed multi-carrier digital subscriber line (DSL) communication systems is limited by the interference among copper lines. This interference can be alleviated by multi-user transmit power allocation. Problem decomposition results in a large number of per-subcarrier problems. Our objective is to solve these nonconvex integer per-subcarrier power control problems at low complexity. For this purpose we develop ten combinatorial heuristics and test them by simulation under a small complexity budget in scenarios with tens of DSL users, where optimal solutions are currently intractable. Simulation results lead us to the conclusion that simple randomized greedy heuristics extended by a specific local search perform well despite the stringent complexity restriction. This has implications on multi-user discrete resource allocation algorithms, as these can be designed to jointly optimize transmit power among users even in large-scale scenarios.