xDSL Access work in ITUT Study Group 15

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xDSL Access work in ITU-T Study Group 15
Presented by Paolo ROSA Counsellor ITU-T Study
Group 15 Optical and other transport networks
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Contents

• About ITU-T SG 15
• Access Scenarios
• xDSL Access

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About Study Group 15 (www.itu.int/ITU-T/studygr
oups/com15)
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ITU-T Study Group 15

• Responsible for studies relating to
• optical and other transport networks, systems and
  equipment including transmission layer related
  standards for access, metropolitan and long haul
  sections of communication networks and relevant
  G-series Recoimmendations.
• Lead Study Group on
• Access Network Transport (ANT)
• Optical Technology

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ITU-T SG 15 Access Network Transport - Targeted
Work and Standardization Plans

• Finalize a Standardization Plan for
• identify existing Recs and standards
• identify areas of overlapping
• identify any missing area
• resolving standardization issues for ANT
• investigate needs for new Recommendations

(www.itu.int/ITU-T/studygroups/com15)
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Many a type of access
SAT
Broadcast
Access Network
Distribution Network
Cable
Longhaul
Copper or F.O.
F.O.
Copper
UNI
SNI
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ITU-T Study Group 15 Structurehttp//www.itu.int/
ITU-T/studygroups/com15/index.asp
Study Group 15 Optical and other transport
networks Peter Wery
ITU-TSB Counsellor Paolo Rosa
Working Party 3 OTN Structure Stephen
Trowbridge
Working Party 4 OTN Technology Gastone
Bonaventura
Working Party 2 Network Signal Proc. Yushi Naito
Working Party 1 Network Access Andrew Nunn
Working Party 5 Projects and Promotion Haruo
Okamura
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Access Scenarios
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Typical Access Network Construction
Central Office (Exchange)
Street Cabinet
Distribution Network
Feeder Network
Underground Feed
Overhead Feed
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Access technological evolution
G-PON 2.5 Gbit/s
OPTICAL ACCESS
622 Mbit/s
50 Mbit/s
VDSL
25 Mbit/s
8 Mbit/s
HDSL/ ADSL
2 Mbit/s
640 kbit/s
ISDN
128 kbit/s
56.6 kbit/s
Analog modems
28.8 kbit/s
Year
9.6 kbit/s
1989
2000
1997
2003
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Capacity, technologies availability
Source Siemens
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Optical access network architecture (G.983.1)
Optical Distribution Network
FTTH
O N U
O L T
Fibre
Copper
FTTB/C
O N U
N T
Fibre
SNI
HOME
Fibre
Copper
O N U
N T
FTTCab
Access network
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Access Network Transport Reference Model
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Access Network Scenarios 1 - 2
Scenario 2
a) Voice/Data over telecom network and Video
over cable b) Voice/Data/Video over 2-way cable
B-ISDN
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Access Network scenarios 3 - 4
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Scenario 3 The use of ADSL or VDSL for video
bandwidth over copper pairs
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Scenario 4 Fibre Access FTTC - FTTH FTTB
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ANT Scenario 5
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Scenario 5 The use of Radio in the Local Loop
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ANT Scenarios 6 - 7
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Scenario 6 - Access using satellites
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Scenario 7 Example of Internet Access
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xDSL Access
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xDSL Market Business Drivers

• xDSL technology allows the provision of
  high-speed Internet access and other broadband
  services over existing copper telephone lines
• Incumbent operators need to exploit their large
  installed base of copper access lines for
  broadband deployment
• Competing operators can exploit incumbent
  operators access lines via unbundling
  agreements
• Competition
• Digital Cable / Cable Modem
• Bi-directional Satellite

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Typical components of an xDSL system
ADSL2 ADSL2 ADSL ADSL lite HDSL SHDSL VDSL
audio/video/data
CUSTOMER PREMISES
CENTRAL OFFICE
xDTU-R
xDTU-C
SNI
T
B-ISDN SN
xDT
xDT
Non-ATM based SN
(e.g. - video server
- IP router)
U-R
U-C
POTS
POTS
PSTN/ISDN
Splitter
Splitter
SN
(Subscriber line)

SN Service Node
xDSL
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ITU-T Recommendations on ADSL (1)

• G.991.1 (G.hdsl) - High bit rate Digital
  Subscriber Line (HDSL) transmission system on
  metallic local lines.
• G.992.1 (G.dmt) - Asymmetrical Digital Subscriber
  Line (ADSL) Transceivers.
• G.992.2 (G.lite) - Splitterless Asymmetrical
  Digital Subscriber Line (ADSL) Transceivers.
• G.992.3 Asymmetric digital subscriber line
  transceivers - 2 (ADSL2.dmt)
• G.992.4 Splitterless asymmetric digital
  subscriber line transceivers - 2 (ADSL2.lite)

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ITU-T Recommendations on ADSL (2)

• G.992.5 Asymmetric Digital Subscriber Line
  (ADSL) Transceivers Extended Bandwidth ADSL2
  (ADSL2plus) (Jan 03)
• G.995.1 - Overview of Digital Subscriber Line
  (DSL Recommendations).
• G.991.2 (G.shdsl) - Single pair High bit rate
  speed Digital Subscriber Line
• G.993.1 (G.vdsl) - Very high bit-rate Digital
  Subscriber Line
• G.994.1, G.996.1 and G.997.1 for tests,
  management and handshake

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(No Transcript)
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G.991.2 (SHDSL) transceivers

• Multi-rate transmission technology
• duplex operation over only two-wire twisted
  metallic pairs. (G.991.1 is for 1-3 pairs).
• Symmetric data rates (scalable)
• One pair mode 192 kbit/s to 2312 Kbit/s (single
  pair mode), in increments of 8 kbit/s, distance
  from 1.8 up to 6.5 km.
• Two-pair mode 384 kbps to 4.624 Mbps
• Many Manufacturers options
• 4-wire operation
• Repeaters, etc.

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G.993.1 (VDSL) transceivers

• Symmetric and asymmetric data rates
• Downstream as high as 5 to 20 Mbit/s
• Upstream 1.6, 2.3, 19 Mbit/s or equal to
  downstream in case of symmetric tx.
• American/Japanese/European (Annexes spectrum
  bandplans for national regulators)
• 300 1 500 m. reach

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G.992.1 - Asymmetric Digital Subscriber Line
transceivers

• One twisted pair
• Payload upstream up to 640 kbit/s
• Downstream up to 6.144 Mbit/s
• Simultaneous Voiceband and N-ISDN possible
• Line Code - DMT (Discrete MultiTone)

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G.992.2 - Splitterless asymmetric digital
subscriber line transceivers

• One twisted pair
• Payload downstream up to 1.536 Mbit/s
• Upstream up to 512 kbit/s
• Line Code - DMT (Discrete MultiTone)

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ADSL versus ADSL2(G.992.1 x G.992.3)

• 2nd generation of ADSL with improvements on
• Loop-reach increase for equivalent bit rates
  (300m)
• Higher down/up bit rates
• loop diagnostics
• Adjustable spectrum shaping during
  operat/initializ
• Power vs traffic control L0(full),L1, L2
• robustness against loop impairments and RFI
• Improved multivendor interoperability
• Improved application support for an all digital
  mode of operation and voice over ADSL operation

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ADSL 2

• Performance
• Downstream 8 Mbit/s to 15 Mbit/s
• Upstream 800 Kbit/s to 1.5 Mbit/s
• Data rate on long distances
• Improved initialization
• Fast Start up 3 seconds
• Fast return to L0 status full operation (0.5 s)
• Additional 256 Kbit/s upstream data rate
• In-line filters for home installation
• Backwards/Legacy compatibility

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ADSL 2 plus - G.992.5

• Performance
• Increase downstream to 16 Mbit/s
• Maybe increase in upstream (Oct. 2003)
• Increase reach (1.5 - 3 Km)
• ADSL doubles the bandwidth (from 1.1 to 2.2
  MHz) with a significant increase of data rates on
  short loops
• Backwards compatibility (needs G.992.3)

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Things in progress in SG15

• Network access
• Home networking (data on in-premises wiring)
• Refinements enhancements xDSL
• Web-based ANT standardization plan
• Optical Transport Network (OTN)
• x-WDM and 40Gbit/s signal channels
• Optical Cross-Connect and Switch
• Fiber characteristics, more channels/fiber
• Network Node Interface for OTN
• Continue as Lead Study Group on
• Access Network Transport
• Optical Technology

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Q.4/15 - Transceivers for customer access and
in-premises phone line networking systems on
metallic pairs

• Current/future work
• Revision of Single-pair High-speed DSL (SHDSL) -
  G.991.2
• G.992.3 Annex C ADSL in same ISDN cable
• G.992.3 Annex L reach extended ADSL over POTS
• G.992.5 Annex J improved Spectral Compatibility
  with ADSL over ISDN improved Spectral
  Compatibility with ADSL over ISDN
• G.992.5 Annex L extended upstream bandwidth
• Very high bit rate DSL (VDSL) G.vdsl.l

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CONCLUSIONS
An overview on the standardizations activities in
ITU-T SG 15 was presented The most recent
standards for access network approved and
consented in October 2002 and January 2003 were
shown Access scenarios, current and future work
provide information about the next future in the
field of access copper network technologies
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Thank you for your attention!

• For further contact, please feel free to contact
• Counsellor for SG 15 Paolo Rosa
• Paolo.rosa_at_itu.int
• Tel [phone] Fax [phone]
• http//www.itu.int/ITU-T