EE535 - PROJECT 3
VDSL - Very High-Rate Digital Subscriber Lines

Although a VDSL standard is not complete, there are certain specifications being considered as achievable goals. Given that VDSL will be used to provide the "last mile" connection between optical networks and the premises, the projected downstream data rates that VDSL will provide are 1/12, 1/6 and 1/3 of the speed of SONET (155.52 Mbps) [ADSL Forum]. These speeds will be available for different line lengths. The following table shows the data rates of VDSL with the corresponding line lengths.

Table 3.1. VDSL Data Rates and line lengths.

Line Length	Downstream Rate
1500 meters	12.96 - 13.8 Mbps
1000 meters	25.92 - 27.6 Mbps
300 meters	51.84 - 55.2 Mbps

The upstream rate being discussed ranges from 1.6 Mbps to the same speed as the downstream channel. Equal upstream and downstream may only be achieved in the shorter lines, and it will require symmetric configurations of VDSL. The first versions of VDSL will be asymmetric, like ADSL.

Telecommunication operators could use VDSL to deliver video-on-demand to the home, using high definition television (HDTV), given the large bandwidth that VDSL allows over a single pair of twisted pair [Teledot].

One other potential application of VDSL is to be used to carry ATM traffic.

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