Very High Speed Digital Subscriber Line

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DSL technologies
Technology ITU-standard
ADSL ANSI T1.413 Issue 2
ITU G.992.1 (G.DMT)
ITU G.992.2 (G.Lite)
ADSL2 ITU G.992.3/4
ITU G.992.3 Annex J
ITU G.992.3 Annex L
ADSL2+ ITU G.992.5
ITU G.992.5 Annex L
ITU G.992.5 Annex M
HDSL ITU G.991.1
HDSL2  
IDSL  
MSDSL  
PDSL  
RADSL  
SDSL  
SHDSL ITU G.991.2
UDSL  
VDSL ITU G.993.1
VDSL2 ITU G.993.2

VDSL or VHDSL (Very High Speed DSL) is a DSL technology providing faster data transmission over a single twisted pair of copper wires. These fast speeds mean that VDSL is capable of supporting new high bandwidth applications such as HDTV, as well as telephone services (Voice over IP) and general Internet access, over a single connection. VDSL is deployed over existing wiring used for POTS (Plain Old Telephone System) and lower-speed DSL connections.

Second-generation VDSL2 systems (ITU-T G.993.2) utilize bandwidth of up to 30 MHz to provide data rates exceeding 100 Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about 300 meters; performance degrades as the loop attenuation increases.

Currently, the standard VDSL uses up to 7 different frequency bands, which enables customization of data rate between upstream and downstream depending on the service offering and spectrum regulations. First generation VDSL standard specified both QAM (Quadrature amplitude modulation) and DMT (Discrete Multi-Tone modulation.) In 2006, ITU-T standardized VDSL in recommendation G.993.2 which specified only DMT modulation for VDSL2.

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[edit] Supply

As of 2006, the market is still small, except in Japan and South Korea, where VDSL is predominant.

  • Belgium
    • Belgacom is providing VDSL in parts of the country (about 6% coverage), but limited to 17 Mbit/s down and 640 kbit/s up, with a monthly download limit of 35 GB. VDSL2 coverage is at 50% in November 2007 (internal Belgacom nota)
  • Brazil
    • Telefonica is providing VDSL in some areas of Sao Paulo with plans ranging from 8 Mbit/s to 30 Mbit/s down and 5 Mbit/s up. The access is provided under Speedy brand and has no aparent bandwidth cap or limitation. The plans are offered in duos (internet + telephony) and trios (internet + telephony + digital IP TV), also known as Triple play (telecommunications), and cost up to $ 300 USD /month.
  • Denmark
    • TDC is providing VDSL in two larger city areas in Copenhagen and Aarhus from February 2008, most urban parts (100 largest city areas) was announced for March 2008, but this was recently changed to September 2008. Cybercity has also announced plans to introduce VDSL.
  • Finland
    • Provided in Oulu by DNA, in Turku by Auria, in various cities by Nebula and in Helsinki by 24 Online. The services provided in Turku and Oulu are actually based on Cisco's LRE. A few universities also provide fiber-optic VDSLs to their students.
  • France
    • Erenis is offering both internet and telephone over VDSL in Paris. The broadband is 60 Mbit/s down and 6 Mbit/s up [1]
  • Germany
    • VDSL is currently available in 28 major cities with 25/5 Mbit downstream/upstream or 50/10 Mbit downstream/upstream. The infrastructure is owned by T-Home, subsidiary of Deutsche Telekom who is planning to invest approximately € 3 billion to set up the requisite VDSL infrastructure in 50 cities until approximately 2007; despite a ruling by the European Commission in December 2004 that would force the company to make parts of this new infrastructure immediately available to competitors, deployment is ongoing. The extent and the terms of infrastructure access are still to be determined. The theoretical bandwidth right now is 100/100Mbit (synchronous line) downstream/upstream but is limited by T-Home to 50/10 Mbit downstream/upstream. Cost for the 25/5 Mbit VDSL service is set at €59,95 and for the 50/10 Mbit VDSL service €64.95, both prices are basic (70 TV channels including some HDTV channels) IPTV channel package, for the premium (100 TV channels including some HDTV channels) IPTV package T-Home is asking an additional €15 which also includes some Pay-TV perks like soccer and movie packages. There no additional charge for data throughput. VDSL from T-Home is bundled with a flat rate.
  • Hong Kong
    • VDSL is offered by HGC. A 10 Mbit/s up and down connection costs less than $15 USD/month with a 12-month contract and $20 USD/month without any contract, both with unlimited traffic.
  • Japan
    • VDSL is indirectly offered in many areas by NTT, Japan's largest telco, in conjunction with FTTH service. It is used as a mechanism to wire apartments and other existing construction as a lower cost alternative to pulling optical fiber to each unit.
  • Malaysia
    • VDSL Network Sdn Bhd [2] one of wireless broadband private company are provide VDSL Line at Terengganu for 10 schools under project Terengganu Cyber School 2007.VDSL Network Sdn Bhd cooperation with Cjaya Incorp ( Korean Company speacialist in VDSL Broadband )base at Portland, Oregon, USA and Seoul, South Korea.At Perlis VDSL Network Sdn Bhd won bidding project planning provide very high-speed broadband 10Mbps to 52Mbps established connection for State of Perlis and benefiting not only the 274,000 residents of the state, but also the sizable student population in and around it.
  • Mauritius
    • VDSL is being rolled out mostly in the Hotel Industry in Mauritius by a private Network Solution Integrator company, Enterprise Data Services Ltd (EDS LTD). EDS is not an ISP, but provide the VDSL in hotels as opposed to the expensive cost of Fiber Optic. The service enables the hotels to provide both wired and wireless Broadband Internet access, Video On Demand and Music on Demand as well as IP telephony to the residents. Since November 2004, till date, EDS has already completed such installation in 12 hotels.
  • Netherlands
    • VDSL roll-out is being tested by the company KPN. KPN hardly invested in ADSL2+ in 2006, despite the current coverage of only 57% (2007), because they see a better future in VDSL.
  • Russia
    • VDSL appeared on 8 February 2005. It is provided by SCTS, offers Internet speeds ranging from 4 Mbit/s / 1.5 Mbit/s to 12 Mbit/s / 6 Mbit/s at Saratov city. Connection costs around €7-50 per month (including 125-1024 MB of external incoming traffic). Traffic costs around €0,03-0,05 per megabyte.
  • Slovenia
    • VDSL appeared on 1 October 2005. It is provided by T-2, offering triple play services with Internet speeds ranging from 1 Mbit/s / 256 kbit/s to 60 Mbit/s / 25 Mbit/s at more than 120 locations across the country (75% coverage). A 10 Mbit/s / 10 Mbit/s connection costs €46 per month.
  • South Korea
    • VDSL is offered in apartments by KT and other several providers, costing about $25-$40 USD/month.
  • Spain
    • VDSL roll-out by Telefonica began in 2005 in selected places in Madrid. Commercial launch up is planned for 2008.
  • Switzerland
    • Used in the Bluewin TV television-over-IP service and in the DSL service with 15 Mbit/s downstream and 1 Mbit/s upstream, introduced in July 2007. The city of Zurich had a vote about putting VDSL infrastructure in place in 2007 which was approved by the voters. This "Fiber to the Home" network will be run by the cities power company and will offer maximum speeds of around 100Mbit bandwidth though it's not clear what the upload speeds or pricing will be. The Swiss telecom giant Swisscom offers VDSL in most of Switzerland.
  • Taiwan
    • VDSL is available in Taiwan in the Fiber To The Building (FTTB) service provided by Chunghwa Telecom, the largest telecommunication company in Taiwan. FTTB has a maximum connection speed of up to 100 Mbit/s downstream and 5 Mbit/s upstream.
  • Turkey
    • Turkish state-regulated monopoly Turk Telekom is said to begin VDSL trials in September 2007 with service planned for 2008 (per article in Turkish daily Hurriyet dated 19 March 2007, p. 10).
  • United States
    • Qwest provides Internet access and television service over FTTN VDSL in Denver, Colorado and Phoenix, Arizona.
    • AT&T provides Internet and television service over VDSL in 25 cities under the trade-name U-Verse. The AT&T service is based on FTTN, Fiber to the Node and FTTP is also used.
    • Verizon offers its FiOS service in some metropolitan areas at speed of up to 50 Mbit/s. The Verizon service is based on FTTP, and normally CAT5e Ethernet (or HPNA over coax) is used to deliver data service throughout the home. However, VDSL is used in MDUs when running CAT5e to individual units is not practical.

[edit] See also

[edit] References

  1. ^ B. Lee, J. Cioffi, et al. (September, 2007). "Gigabit DSL". IEEE Transactions on Communication. 55 (9): 1689-1692. 

[edit] External links