Dynamic spectrum management for mixtures of vectored and non-vectored DSL systems

A number of Vectored DSL system prototypes have confirmed the substantial performance gains from Far-End Crosstalk (FEXT) cancellation. With field trials and initial deployments expected to materialize in the next two years, a very important question is how such Vectored DSL systems can coexist with non-vectored DSL systems sharing the same cable. This paper shows that the performance gains for Vectored DSL systems can be maintained in a mixture of vectored and non-vectored lines if a Spectrum Management Center (SMC) is assigned to control the impact of crosstalk from the non-vectored to the vectored lines. Simulation results are presented for certain scenarios, first, to illustrate that an Iterative Waterfilling strategy can achieve performance near the optimal, and second, to explore the trade-off between limiting the rates of the non-vectored lines and boosting the rates of the Vectored DSL systems.