MODELLING AND MITIGATION OF ALIEN CROSSTALK FOR DSL SYSTEMS
.fast, Alien Crosstalk Mitigation, Linear Prediction, Measurements.
G.fast is the most recent ITU-T standard for copper-based transmission, which targets copper topologies with short distances and adopts a bandwidth of 106 MHz extensible to 212 MHz. In several scenarios, G.fast systems will be composed by or coexist with uncoordinated (or alien) lines, which are sources of strong crosstalk, because are not part of the vectored group. This document presents a formulation to explain the performance of the methods according to the number of the alien lines in the environment, the mechanism that defines the interference correlation and an alien mitigation method for downstream DSL transmission impaired by multiple interferers. Simulation results show that alien crosstalk mitigation methods can indeed improve the performance of G.fast systems, but under specific conditions. We have contrasted these situations and we provide guidelines about the feasibility of the crosstalk mitigation technique in scenarios with distinct alien lines. Additionally, the proposed method shows promising results when compared with literature methods. As support for the simulations, we also present a set of alien crosstalk measurements.