Comparison of interference mitigation techniques for next generation DSL systems

The next digital subscriber line (DSL) generation, called G.fast, extends the frequency band up to 212MHz and achieves Gigabit data-rates. Vectoring technology cancels the performance-limiting crosstalk among DSL lines on a signal level, but requires co-located line termination. Differently, dynamic spectrum management level 2 (DSM-L2) coordinates the transmit power spectra among interferers and thus, does not require all line termination units to be co-located. In this work we analyze the data-rates of G.fast under full vectoring, partial vectoring restricted to groups of users, and non-vectoring scenarios. We also propose interference alignment (IA) as an alternative method to DSM-L2 for dealing with the interference in G.fast and show that IA is superior to DSM-L2 in non-vectoring scenarios. Furthermore, we also propose time division multiple access (TDMA) for coordination of multiple vectoring groups in partial vectoring scenarios.