Combined trellis coding and DFE through Tomlinson precoding

The authors propose and evaluate a receiver architecture which combines the power of a decision feedback equalizer (DFE) with trellis coding, while allowing for minimal decoding delay in such a way that the total gain of the system is additive. The system is based on a structure that transposes the feedback filter of the DFE into the transmitter and, for high-order constellations, provides negligible increase in transmitter power. The first known hardware realization of a high bit rate digital subscriber line (HDSL) system that achieves the coding gain provided by a trellis code in addition to the equalization gain provided by the DFE is presented. A system whose complexity of implementation is comparable to that of a typical DFE and an independent Viterbi decoder is proposed