Patent ID: 7738541

Claim:
A method for implementing smart digital subscriber line (DSL) for long reach digital subscriber line (LDSL) systems, the method comprising: selecting a spectral mask by one of a central office and customer premise equipment (CPE) based upon performance criteria, wherein selecting a spectral mask further comprises selecting a spectral mask from a number of upstream masks (U 1 , U 2 , U 3 , . . . , Un) and a number of downstream masks (D 1 , D 2 , D 3 , . . . , Dn), wherein one of the number of upstream masks is defined by the following relations, wherein f is a frequency band in kHz and U 1 is the value of the mask in dBm/Hz: for 0<f≦4, then U 1 =−97.5, with max power in the in 0-4 kHz band of +15 dBm; for 4<f≦25.875, then U 1 =−92.5+23.43×log 2 (f/4); for 25.875<f≦60.375, then U 1 =−29.0; for 60.375<f≦90.5, then U 1 =−34.5−95×log 2 (f/60.375); for 90.5<f≦f1221, then U 1 =−90; for 1221<f≦1630, then U 1 =−99.5 peak, with max power in the [f, f +1 MHz] window of (−90−48×log 2 (f/1221)+60) dBm; and for 1630<f≦11040, then U 1 =−99.5 peak, with max power in the [f, f+1 MHz] window of −50 dBm; and activating the selected spectral mask based on at least one of customer premise or central office capabilities.