Service-specific data transmission over ADSL communications systems

The paper proposes use of lower quality-of-service data links, which are not usable for ADSL (asymmetrical digital subscriber line) services, and refers to DMT (discrete multi-tone) modulation, and describes how QoS is defined by means of a signal-to-noise vector. It presents SNR equations, and shows an ADSL reference diagram. The paper plots bit loading spectra under noise conditions, proposes ADSL data rate increases from 64 kbit/s to 280 kbit/s, confirmed by experiments, using ISDN and HDSL protocols in a 590-pair cable.