Distance-gains by multiple-duplex transmission, coding, and shaping for HDSL

The maximum distance over which reliable high rate digital transmission over twisted pair lines is possible can be increased substantially by multiple-duplex transmission, channel coding, and signal shaping. Simple equations are derived to transform SNR (signal to noise ratio)-gains into distance gains. Numerical examples are given for a transmission of 2.048 Mb/s over twisted pairs with line diameters 0.4 mm and 0.6 mm (AWG 26 and AWG 22). A new signal shaping method without scrambling of data bits is proposed, by which a SNR-loss due to error multiplication in the descrambling procedure is avoided.<
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