Operational Experiences of G.fast in the UK...TNO Ultrafast Broadband Seminar 2015 – slide 3...
Transcript of Operational Experiences of G.fast in the UK...TNO Ultrafast Broadband Seminar 2015 – slide 3...
Operational Experiences of G.fast in the UK
John MacDonald, BT TNO Ultrafast Broadband Seminar 2015 [email protected]
© British Telecommunications plc
TNO Ultrafast Broadband Seminar 2015 – slide 2
Presentation outline
� BT’s Ultrafast Vision
� BT’s G.fast Technology Trials
– Ipswich
– Hethersett
– St James
� Field Measurements
� Conclusions
© British Telecommunications plc
TNO Ultrafast Broadband Seminar 2015 – slide 3
BT’s ultrafast broadband vision� BT has been a believer in high speed
copper for over a decade and has been
working with industry to develop G.fast.
� On 30th January 2015, BT CEO Gavin
Patterson announced our Ultrafast
broadband vision and G.fast is at the
heart of that vision.
� Ten-year vision of 500Mbps available
across most of the UK.
� Premium 1Gbps fibre broadband
services for high-demand customers.
© British Telecommunications plc
TNO Ultrafast Broadband Seminar 2015 – slide 4
Superfast fibre speeds
� Currently around 75% of UK premises have been passed with the first generation of our
fibre technology, giving speeds of up to 80Mbps. BT is working with BDUK to reach ~95% of
UK premises.
� To do this, we have enabled over 60,000 of our 88,000 cabinet locations in the network with
power, fibre and equipment currently delivering superfast using VDSL2.
� The typical distance from a cabinet to the customer premises is ~350m.
350m typical
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TNO Ultrafast Broadband Seminar 2015 – slide 5
BT’s vision for G.fast deployment
G.fast from existing location G.fast from new location
� The original vision for G.fast was deployment at the Distribution Point. The typical
distance from the DP to the home in BT’s network is ~35m, making speeds of up to 1Gbps
achievable.
� However, our simulation work, lab measurements and technology trials showed that G.fast
has the potential to deliver several hundreds of megabits on longer loops.
� By extending the reach of G.fast towards 350m, this makes the existing PCP locations ideal
for reaching significant numbers of customers whilst leveraging our NGA investment.
� For customers out of reach, copper / network rearrangement will be required
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TNO Ultrafast Broadband Seminar 2015 – slide 6
Large-scale G.fast trials
� BT will run two large-scale trials of G.fast technology in
Huntingdon, Cambridgeshire, and Gosforth, Newcastle-upon-
Tyne, starting in the summer of 2015. Around 2000 premises
will be covered in each pilot area.
� BT will conduct a further trial of G.fast to Multiple Dwelling
Units (MDUs) and businesses in Swansea, South Wales.
� Trial participants will gain access to speeds of up to several
hundred megabits per second.
� The pilots will be run by Openreach, so the infrastructure will
be available to all Communications Providers on equal
terms; end-user customers will be offered the chance to
participate via their own service provider.
� We are currently running small-scale technical trials in
Suffolk and Norfolk, which will help inform our decisions for
the large-scale trials.
Gosforth
Huntingdon
Swansea
Hethersett
Ipswich
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TNO Ultrafast Broadband Seminar 2015 – slide 7
World’s first technical trial of G.fast, Ipswich, SuffolkFootway box
DPU� 3 customers connected to 1 DPU� Operational since October 2013
19m
47m66m
XGPON backhaulDPU
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Ipswich G.fast trial topology
� The trial used existing duct structures and DP locations, but created a separate overlay to prevent interference to existing DSL services
G.fast is served via a diversecable infrastructure, and does not co-exist with existing DSLservices in any cable binder
or joint enclosure.
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TNO Ultrafast Broadband Seminar 2015 – slide 9
Ipswich G.fast trial performance results
� Chart shows aggregate data rates for shortest and longest trial lines for
different G.fast start frequencies and with vectoring enabled and disabled.
� Results showed that G.fast worked as expected.
� Vectoring critical in order to deliver the maximum bandwidth.
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TNO Ultrafast Broadband Seminar 2015 – slide 10
G.fast technology trial, Hethersett, Norfolk
DPU
Remote power
• 7 DPU’s, 23 customers, all u/g cables• Overlay network, 2nd lines installed
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TNO Ultrafast Broadband Seminar 2015 – slide 11
Spectrum compatibility between G.fast and VDSL2
� ITU-T G.9700 defines that G.fast can operate over the frequency spectrum
from 2MHz to 106MHz.
� As this overlaps with the VDSL2 spectrum (0.14 to 17.7MHz) it is essential to
preserve spectrum compatibility to avoid interference between VDSL2 and
G.fast signals operating in the same cable binders.
� For Hethersett, this was achieved by starting the G.fast spectrum at 23MHz,
well above the upper frequency of VDSL2.
VDSL2 G.fast
17.7 23 106 MHz
Guard Band
0.14
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TNO Ultrafast Broadband Seminar 2015 – slide 12
The results from our Hethersett G.fast technology trial
Overlay network, 23-106MHz operation� The Hethersett technology trial is using
G.9700/G.9701 compliant G.fast with a
start frequency of 23MHz.
� Good correlation observed between the
field results and lab measurements.
� The equipment is already delivering over
500Mbps aggregate at distances of
~120m.
� It is also delivering aggregate speeds in
excess of ~150Mbps at 300m.
� We expect this performance to continue
to improve as standards and
developments evolve.
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TNO Ultrafast Broadband Seminar 2015 – slide 13
Loop Characterisation
� As part of Hethersett trial we performed some loop characterisation
measurements on trial lines
� The following measurements were performed on each line:
- Insertion loss of the pair from DPU to NTE
- Ambient noise at DPU end of new pair
- Ambient noise at CPE end of new pair
- Ambient noise on existing line at CPE
- Calculation of Hlog (pre ITU-T G.997.2)
� Some examples shown on the following slides …
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Example line #1
Est. length from TDR: 28 mEst. length from IL: 38 mEst. length from Hlog: 79 m
Note: IL and TDR estimates do not include umbilical and modem lead. Hlog is not calibrated.
VDSL crosstalk from existing line
FM RadioFM Radio
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Example line #2
Est. length from TDR: 81 mEst. length from IL: 71 mEst. length from Hlog: 99 m
Note: IL and TDR estimates do not include umbilical and modem lead. Hlog is not calibrated.
VDSL crosstalk from adjacent lines
FM RadioFM Radio
PLT
VDSL crosstalk
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Example line #3
Est. length from TDR: 30 mEst. length from IL: 40 mEst. length from Hlog: 62 m
Note: IL and TDR estimates do not include umbilical and modem lead. Hlog is not calibrated.
Much noisier line
FM Radio
VDSL crosstalk
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Noise floor measurements� Network measurements analysed to calculate noise floor as a percentage of frequency
spectrum.
� Many lines have a measured noise floor below -150dBm/Hz.
� The lower noise floor gives a material boost to performance, especially on long lines.
At the DPU between 23MHz to 106MHz At the CPE between 23MHz to 106MHz
-140 < Noise
-145 < Noise < -140
-150 < Noise < -145
-155 < Noise < -150
-140 < Noise
-145 < Noise < -140
-150 < Noise < -145
-155 < Noise < -150
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Planned G.fast technical trial, St James, Suffolk
� 20 DPU’s, ~60 customers, mainly o/h cables
� Overlay network, 2nd lines currently being installed
DPU
Customer
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TNO Ultrafast Broadband Seminar 2015 – slide 19
Conclusions
� BT has announced a vision for Ultrafast Broadband with G.fast
at its heart.
� Currently running several small scale technology trials of G.fast
to gain network experience of deploying G.fast and to provide
input into our plans for larger scale pilots.
� Results from the technology trials show good correlation
between laboratory and field measurements.
� G.fast can be successfully deployed to deliver Ultrafast
Broadband over 250m of cable.
� There are challenges to the Industry to further improve G.fast
performance.
© British Telecommunications plc
TNO Ultrafast Broadband Seminar 2015 – slide 20