Vectoring-Based Dynamic Spectrum Management for G.fast Multi-User Full-Duplex Transmission

Full-duplex transmission is a new challenging technique emerging in DSL networks that may double the spectral efficiency by transmitting in the downstream (DS) and upstream (US) at the same time on identical frequencies. Unfortunately, this leads to severe near-end crosstalk (NEXT) interference in addition to the conventional far-end crosstalk (FEXT) among the lines within the cable binder. To limit the NEXT impact by balancing the user transmit spectra, tailored vectoring-based dynamic spectrum management techniques are vital. In this paper, we develop such a algorithm assuming perfect NEXT cancellation at the access node. This assumption in combination with US-DS duality theory allows to reformulate the DS-US structure of the non-convex weighted sum-rate maximization problem into an easier US-US structure. The reformulated problem is then solved with low-complexity iterative fixed-point power updates. Simulations of a G.fast multi-user FDX transmission demonstrates significant improvements over standard TDD transmission.