Throughput and Delay of DSL Dynamic Spectrum Management with Dynamic Arrivals

In modern DSL networks, crosstalk among different lines (i.e., users) is the major source of performance degradation. Dynamic spectrum management (DSM) refers to a set of techniques to mitigate the effect of crosstalk leading to spectacular performance gains. However the main research efforts in DSM aim at only physical layer performance whereas the true end user experience depends on what they see at the application rather than the physical layer. Upper layer performance metrics like throughput and delay may be much more important to improve the user satisfaction. To that end, we provide a framework to study upper layer performance by looking at scheduling and DSM together. We show how optimal scheduling can be combined with optimal DSM and provide throughput-optimal scheduling algorithms which require only polynomial complexity. We furthermore present extentions that significantly improve delay performance by using the specific structure of the underlying problem.