Emerald Group Publishing Limited
Copyright © 2004, Emerald Group Publishing Limited
ITU has reached agreement on a new global standard that specifies the application of the two main technologies used for encoding signals for DSL – Discrete MultiTone (DMT) technology and Quadrature Amplitude Modulation (QAM) – to very high-speed digital subscriber line (VDSL) technology. VDSL gives multi-megabit network access via ordinary telephone subscriber lines, allowing operators to offer a “triple play” of services – multiple high-quality digital video streams, high-speed Internet access and voice.
Peter Wery, Chairman of ITU-T Study Group 15, said:
Future evolution of the VDSL standard, promising even higher bit rates and longer distances, will be based on the DMT technology used for ADSL, thus establishing a single world-wide standard. This will allow the broadband telecom consumer to benefit from the economies of scale offered by global volumes as well as the technological innovation driven by competition.
Once network operators have implemented the new standard, customers will be able to view multiple TV programmes, access the Internet, and talk on the phone – all at the same time, through one single phone line.
This agreement provides some of the technical know-how necessary to roll out the services defined by the ITU-T FS-VDSL focus group.
VDSL permits the transmission of asymmetric and symmetric data rates up to tens of Mbit/s. This will allow network operators to offer fully integrated voice, video and high-speed Internet access to residential customers. VDSL can be deployed from central offices or from optical fibre-fed cabinets located near customer premises. Actual bit rates obtained will depend on the distance between the central office/cabinet and the customer premises and can be up to 50 Mbits downstream, but will typically be closer to 23 Mbits and 4 Mbits upstream.