Blind equalization for digital cable transmission with Tomlinson-Harashima precoding and shaping

A new system concept for high-rate digital transmission over twisted pair lines with precoding is presented. To avoid retransmission of channel data, filters at the transmitter side are fixed and designed for a reference application. Intersymbol interference caused by mismatch of designed filters and actual situation, is cancelled by an adaptive FIR equalizer. Implementation is thereby simplified considerably compared to the case of optimum tuned filters, whereas the resulting SNR-loss is negligible. Because Tomlinson-Harashima precoding is not suited for many blind equalization algorithms, a modification of the precoder is proposed, resulting in a structure called dynamics shaping, which enables blind equalization by the Sato algorithm