VDSL
Very high speed digital subscriber line transceivers | |
Status | In force |
---|---|
Year started | 2001 |
Latest version | (11/15) November 2015 |
Organization | telecommunication |
License | Freely available |
Website | www |
Very high-speed digital subscriber line (VDSL) (ADSL2+).
VDSL offers speeds of up to 52
Second-generation systems (VDSL2; ITU-T G.993.2 approved in February 2006)[5] use frequencies 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 metres (980 ft); performance degrades as the local loop attenuation increases.
Conceptual development
The concept of VDSL was first published in 1991 through a joint
VDSL2 standard is an enhancement to ITU T G.993.1 that supports asymmetric and symmetric transmission at a bidirectional net data rate up to 400 Mbit/s on twisted pairs using a bandwidth up to 35 MHz.
VDSL standards
A VDSL connection uses up to seven frequency bands, so one can allocate the data rate between
Version | Standard name | Common name | Downstream rate | Upstream rate | Approved on |
---|---|---|---|---|---|
VDSL | ITU G.993.1 | VDSL | 55 Mbit/s | 3 Mbit/s | 2001-11-29 |
VDSL2 | ITU G.993.2 | VDSL2 | 200 Mbit/s | 100 Mbit/s | 2006-02-17 |
VDSL2-Vplus | ITU G.993.2 Amendment 1 (11/15) |
VDSL2 Annex Q VPlus/35b |
300 Mbit/s | 100 Mbit/s | 2015-11-06 |
VDSL2
VDSL2 is an enhancement to VDSL designed to support the wide deployment of triple play services such as voice, video, data and high-definition television (HDTV) VDSL2 is intended to enable operators and carriers to gradually, flexibly, and cost-efficiently upgrade existing xDSL infrastructure.
The protocol is standardized in the International Telecommunication Union telecommunications sector (ITU-T) as Recommendation G.993.2. It was announced as finalized on 27 May 2005,[5] and first published on 17 February 2006. Several corrections and amendments were published from 2007 to 2011.[2]
VDSL2 permits the transmission of asymmetric and symmetric aggregate data rates up to 300+ Mbit/s
Vplus/35b
Vplus is a technology to achieve higher speeds over existing VDSL2 networks. It was developed by Alcatel-Lucent and standardised in November 2015 in ITU G.993.2 Amendment 1 as VDSL2 profile 35b.[2] It promises to deliver speeds of up to 300 Mbit/s downstream and 100 Mbit/s upstream on loops shorter than 250 m. On longer loops, Vplus falls back to VDSL2 17a vectoring performance.[9] Vplus uses the same tone spacing as VDSL2 17a to allow vectoring across Vplus (35b) and 17a lines, and thus mixed deployments and a smooth introduction of Vplus.[9]
Profiles
The VDSL1 standard has three bandplans: Annex A (Asymmetric BandPlan), Annex B (Symmetric BandPlan) and Annex C (Fx BandPlan). Annex A and Annex B were formerly called Plan 998 and Plan 997 respectively. VDSL1 Annex C is intended for use in Sweden only and it uses a variable separating frequency between the second downstream band, and the second upstream band. All VDSL1 bandplans have spectrum up to 12 MHz, so the length of the copper loops must be shorter than ADSL.[10][11]
The VDSL2 standard defines a wide range of profiles that can be used in different VDSL deployment architectures; in the central office, in the cabinet or in the building for example.[12]
Profile | Bandwidth (MHz) |
Number of total carriers
|
Carrier bandwidth (kHz) |
Maximum aggregate downstream transmit power (dBm) |
Max. Mbit/s )
|
Max. upstream throughput (Mbit/s) |
---|---|---|---|---|---|---|
8a | 8.832 | 2048 | 4.3125 | +17.5 | 50 | 16 |
8b | 8.832 | 2048 | 4.3125 | +20.5 | 50 | 16 |
8c | 8.500 | 1972 | 4.3125 | +11.5 | 50 | 16 |
8d | 8.832 | 2048 | 4.3125 | +14.5 | 50 | 16 |
12a | 12 | 2783 | 4.3125 | +14.5 | 68 | 22 |
12b | 12 | 2783 | 4.3125 | +14.5 | 68 | 22 |
17a | 17.664 | 4096 | 4.3125 | +14.5 | 150 | 50 |
30a | 30.000 | 3479 | 8.625 | +14.5 | 230 | 100 |
35b | 35.328 | 8192 | 4.3125 | +17.0 | 300 | 100 |
VDSL2 vectoring
Vectoring is a transmission method that employs the coordination of line signals for reduction of
Although technically feasible, as of 2022, vectoring is incompatible with local-loop unbundling, but future standard amendments could bring a solution.[citation needed]
VDSL2+ Supervectoring
See also
References
- ^ "ITU-T Recommendation G.993.1: Very high speed digital subscriber line transceivers (VDSL)". Retrieved 24 July 2016.
- ^ a b c "ITU-T Recommendation G.993.2: Very high speed digital subscriber line transceivers 2 (VDSL2)". Retrieved 24 July 2016.
- ^ "VDSL Speed". HowStuffWorks. 21 May 2001.
- ^ "G.993.1 (06/04)". ITU.
- ^ a b "New ITU Standard Delivers 10x ADSL Speeds: Vendors applaud landmark agreement on VDSL2". News release. International Telecommunication Union. 27 May 2005. Retrieved 22 September 2011.
- ^ "G.993.2 : Very high speed digital subscriber line transceivers 2 (VDSL2)".
- ^ "Tyrone Fabrication Ltd., Eircom VDSL". Archived from the original on 31 January 2012. Retrieved 8 March 2012.
- ^ Broadband Forum (2016-07-01). "TR-348 Hybrid Access Broadband Network Architecture" (PDF). Retrieved 2018-07-01.
- ^ a b Keith Russell; Paul Spruyt; Stefaan Vanhastel (16 October 2014). "Vplus gets more out of VDSL2 vectoring". Alcatel-Lucent. Archived from the original on 25 July 2015.
- ^ "IT-T xDSLxDSL Standards" (PDF). International Telecommunication Union (ITU). Retrieved 2024-01-08.
- ^ "Very high speed digital subscriber line transceivers". International Telecommunication Union (ITU). Retrieved 2024-01-08.
- ^ "G.993.2 : Very high speed digital subscriber line transceivers 2 (VDSL2)".
- ^ tsbmail (2013-06-14). "G.993.5 : Self-FEXT cancellation (vectoring) for use with VDSL2 transceivers". Itu.int. Retrieved 2013-07-04.
- ^ "The ITU-T's New G.vector Standard Proliferates 100 Mb/s DSL" (PDF). Archived from the original (PDF) on 2018-12-27. Retrieved 2016-07-24.
- ^ "What is VDSL Vectoring, SRA and G.INP ?". www.draytek.co.uk. Retrieved 2021-01-25.
- ^ "Telekom: Magenta Zuhause XL - Alle Tarifdetails auf teltarif.de!". 2020-07-14.
- ^ heise online (2018-08-16). "Supervectoring: Telekom vermarktet VDSL mit 250 Mbit/s" (in German).