An Optimal Multi-User, Multi-Service Algorithm for Dynamic Spectrum Management in DSL

Crosstalk between neighbouring lines is the major limiting factor in the performance of modern DSL systems. Dynamic Spectrum Management (DSM) techniques have been proposed to mitigate the effects of crosstalk. Many of these techniques address the problem from a multi-user perspective, considering crosstalk effects during bit-loading. Previous work has considered the case where each DSL line carries one constant bit-error-rate (BER) service. However, to date the multi-user, multi-QoS scenario has not been considered. This work considers the case where each line may carry more than one service with different BERs. Reducing the BER requirements for a given service reduces the power requirements and thus reduces crosstalk, improving the performance of all users in the binder group. The optimal approach for the two service case is derived and simulation results are presented.