Comparison of preceding schemes for digital subscriber lines

Preceding at the transmitter side is a practicable method for transmission over intersymbol interference channels, In contrast to decision-feedback equalization no error propagation occurs and coded modulation can be applied as for the intersymbol interference free channel, In this paper, Tomlinson-Harashima preceding and flexible preceding are analyzed and compared, The dualities and differences are discussed, The focus of interest is the application of preceding to fast digital transmission over twisted pair lines, such as high-rate or asymmetric digital subscriber lines, It turns out that flexibility-which is not necessary in the specific application, digital subscriber lines-of flexible preceding is paid with a performance loss compared to Tomlinson-Harashima precoding.