Blind equalization techniques for xDSL using channel coding and preceding

A new concept for digital communication over severe intersymbol interferenc e producing channels, e.g., high-rate digital transmission over twisted pai r lines (xDSL techniques) is proposed including channel coding, preceding, equalization, and synchronization, Channel coding improves data reliability or tolerable signal attenuation, e.g., field length, whereas a nonlinear p redistortion method, a modification of the well-known Tomlinson-Harashima p receding (THP) including signal shaping and dynamics limitation st the rece iver side, is used in order to cope with intersymbol interference. In contr ast to prior approaches, a fixed compromise precoder together with a linear blind adaptive fine tuning equalizer at the receiver side is proposed in o rder to avoid any retransmission of channel measurement data to the receive r. By this, neither a blocking of bidirectional communication can happen no r sophisticated start-up protocols are necessary. For this purpose new algo rithms for blind adaptive equalization are introduced which are able to ope rate at very low signal-to-noise ratios due to channel coding and for highl y correlated data sequences, typically for the application of preceding tec hniques. Additionally, methods for symbol timing synchronization are propos ed.