Implementation aspects of nonlinear precoding for G.fast — coding and legacy receivers

Hybrid copper/fiber networks bridge the gap between the fiber link at the distribution point and the customer by using copper wires over the last meters. The G.fast technology has been designed to be used in such a fiber to the distribution point (FTTdp) network. Crosstalk management using MIMO precoding is a key to the required performance of FTTdp. With higher frequencies used on copper wires, nonlinear precoding schemes such as Tomlinson Harashima precoding are discussed as an alternative to linear precoding. This paper focuses on the advantages and losses of Tomlinson Harashima precoding used for coded transmission on twisted pair cable bundles. A performance loss model for the Modulo loss in coded transmission is presented. Interoperability between linear and nonlinear precoding is discussed.