Determination of ADSL data rates over subscriber lines using practical DMT modulation simulation

Asymmetric Digital Subscriber Line (ADSL) is a high speed access technology which can be used for asymmetric multimedia and Internet applications. A common problem facing telecommunication service providers (Telcos) is to determine beforehand how many customers could be upgraded from existing plain analog voice services, or any other service, to ADSL(+voice) over the same local loop. In this paper the ADSL downstream throughput rate for a specified part of a network, which includes additive white Gaussian noise (AWGN), near-end crosstalk (NEXT) and far-end crosstalk (FEXT) between adjacent lines, is determined. Services being considered are: ADSL, ISDN and El. A bit loading algorithm [1], as used in practical Discrete Multi-Tone (DMT) ADSL modems, is used to determine ADSL downstream data rates.