Two design techniques for adaptive transceivers for digital subscriber lines (DSL)

Two techniques for using adaptive transceivers for digital subscriber lines (DSL) are studied. Both methods utilize preprocessors before modulation and transmission of signals. The performance of these transceivers is compared with that of a conventional transceiver, with no preprocessor, on some loops within the CSA (carrier serving area) design rules. It is found that when self near-end crosstalk (NEXT) is the predominant impairment, using adaptive transmitters in addition to adaptive decision-feedback equalizers (DFEs) offers to advantage over using fixed transmitters with DFEs. However, the results indicate that adaptive transmitters can be used to eliminate precursor intersymbol interface (ISI) without substantial performance penalty. This leaves the receiver the sole task of mitigating the effects of added interference and postcursor ISI