Estimations of G.fast transmission performance over phantom modes

This article deals with newly developed G.fast transmission system and its application together with phantom mode transmissions. The main motivation is to estimate the performance of G.fast over phantom circuits for various real scenarios, which are based on measurements performed for a multi-quad metallic cable. Since the performance of G.fast is mostly limited by the crosstalk and especially by far-end crosstalk (FEXT), the estimations are focused mainly on comparisons for FEXT dominating scenario and the situation with completely eliminated FEXT contributions in a metallic cable binder as well as potential impedance mismatches. However, the full coordination of transmitted DMT symbols by vectored discrete multitone modulation (VDMT) for all subscriber lines in large cable binders is computationally very demanding in practice. The conclusions presented within this paper can be helpful to decide potential benefits of phantom mode transmission method in practice.