VDSL2

1
VDSL2

• and the C559 review

Paul Brooks pbrooks_at_layer10.com.au
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Timeline for xDSL
Feb 2006-2007
ADSL1 initially developed by ATT/Bell Labs in
1989 to deliver video predates the development
of WWW
2003-2007
2002,2005-2007
2003
1999-2003
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Why?
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Agenda

• DSL Redux
• ADSL 2
• VDSL2 compared
• VDSL2 Bandplans
• VDSL2 benchmarks
• Bonding Packet Transfer Mode
• DSM Dynamic Spectrum Management

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ADSL2

• 512 tones
• 25 tones upstream
• 473 tones downstream
• max 60kbps per tone
• Frequency band up to 2.2 MHz

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VDSL2

• Several Band-plans
• 7200 tones (up to 30MHz)
• 3 upstream bands
• 2 or 3 downstream bands
• Same encoding and signalling per tone - 60 kbps
• Frequency band up to 12/17/30 MHz

VDSL2 is effectively ADSL2
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Several Bandplans(1)
B8-4 is a 998 plan. B7-5 is a 997 plan

• Its not as simple as 997 bandplans are more
  symmetric, 998 bandplans are more asymmetric..

B8-4
B7-5
B7-5
B8-4
Assumptions 12 MHz band plans PIUT 40 revised No
UPBO 9 x VDSL2 equal length
(Example - C559 VDSL2 working group benchmark
illustration only!)
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Several Bandplans(2)

• G.993.2 02/2006

• Annex A (US) 9 plans based on Annex M ADSL2

• Annex B (Euro) 6 x 997 plans and 7 x 998
  plans up to 12 MHz

• Annex C (Japan) 1 band plan over ISDN, up to 30
  MHz

• Annexes D, E, F, G, H, I, J, K all for further
  study

But waittheres more
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Several Bandplans(3)

• G.993.2 Amendment 1 Nov 2006 draft

• Annex A (US) 8 downstream x 11 upstream (some
  not compatible with each other) 80 plan
  variations, with max at 8/12/17/30 MHz

Exercise Pick One (1) only bandplan for use
throughout Australia

• Annex B (Euro) 10 x 997 plans and 16 x 998
  downstream plans up to 8/12/17/30 MHz

• Annex C (Japan) 4 minor band plan variants, up
  to 30 MHz

This VDSL2 stuff is very fresh!
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Ob-Disclosure

• Communications Alliance C559 Deployment Rules
  Review
• Layer10 representing
• Preliminary information is from working drafts
  subject to change before publication.

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Multiple Bandplans dont coexist

• Frequencies that one line uses for upstream, and
  another line uses for downstream, interfere and
  destroy each other
• Overall performance drops to lowest common
  denominator for both
• Every service must use the same tones for
  upstream and downstream, without overlap
• All must use the same bandplan

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Bandplan Choice

• Chosen Bandplan isEuropean Annex B 998 Plan
  B8-11 to 17 MHz(from Amendment 1 still to be
  completed)

• Little/No benefit to go to 30MHz, but 17 MHz
  provides good speed out to 600m
• 998 plan maximises downstream capacity for IPTV,
  Internet content downloads
• Still retains good upstream (5-20 Mbps at 800m)
  upstream capacity meets or beats eSHDSL symmetric
  services at all distances

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VDSL2 Deployment Classes

• ADSL2 Deployment Classes
• 6h ADSL2 (Annex A) (unlimited distance)
• 6j ADSL2 Annex M EU-40
• 6k ADSL2 Annex M EU-52
• 6l ADSL2 Annex M EU-56
• 6m ADSL2 Annex M EU-60
• 6n ADSL2 Annex M EU-64

• VDSL2 Deployment Classes
• 10h VDSL2
• 10j VDSL2 Annex M EU-40 in US0 upstream
• 10k VDSL2 Annex M EU-52 in US0 upstream
• 10l VDSL2 Annex M EU-56 in US0 upstream
• 10m VDSL2 Annex M EU-60 in US0 upstream
• 10n VDSL2 Annex M EU-64 in US0 upstream
• NOT any of the further Annex M-like EU-XX
  beyond EU-64

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VDSL2 Benchmarks

• Benchmark 10h modelled worst-case performance

Preliminary Only Do Not Rely On These!
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/end C559

• Back to ITU-T G.993.2
• (but still subject to amendments!)

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Other VDSL2 tricks

• Bonding
• 2 8 parallel VDSL2 services together, acting as
  a single channel (needs compatible CPE)
• 80 Mbps upstream, 640 Mbps downstream anyone? ?
• Packet Transfer Mode (PTM)
• Ethernet-in-the-first-mile (EFM) 802.3ah framing
  is supported natively
• no more fiddling with ATM PVCs in the DSLAM or
  modem required
• 5 increased performance from reduced overheads

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DSM

• Dynamic Spectrum Management
• Adjusts transmit power in each line to
  time-variable external crosstalk, to optimise
  bandwidth for all lines in the binder by reducing
  cross-talk
• No DSM (current situation) assumes each line is
  greedy worst-case modelling leads to
  conservative performance
• DSM Level 1 static spectrum shaping to avoid
  crosstalk each line tries to optimise PSD shape
  and be polite in isolation
• DSM Level 2 dynamic spectrum shaping each
  line talks to neighbours and all optimise PSD to
  try to be polite
• DSM Level 3 MIMO cross-talk cancellation
  reverse crosstalk signal calculated and added in
  real-time to cancel out at the far end

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DSM Level 2

• Algorithms developed fairly recently
• Iterative Water-Filling (2002)
• Optimal Spectrum Balancing (2004)
• Iterative Spectrum Balancing (2005)
• Autonomous Spectrum Balancing (2006)
• Not available from DSLAM vendors currently,
  although some are preparing products and
  management systems to support DSM.

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DSM Level 2
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DSM Level 3

• Full MIMO Crosstalk Cancellation
• Ask Dr John Papandriopoulosin about 3 5 years
  

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Wrapup

• Its easy to offer 50Mbps access lines, if you
  know the top 40 Mbps will never be able to be
  used

Me.

• Great access network speeds are one thing be
  careful the backhaul can feed the access or
  there is local-enough content to avoid using the
  backhaul

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VDSL2 wont solve everything

• Some problems will be made worse by VDSL2

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Thank you

• pbrooks_at_layer10.com.au

www.layer10.com.au