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22 E L EC TR I C AL CONNEC T I ON
W I N T E R 20 1 6
FAST TRACK TO THE FUTURE
I
n October 2015, nbn (formerly
NBN Co) completed a trial of G.Fast
technology, which will allow users
to achieve high bit rates on existing
copper wire.
So what exactly is G.Fast? And how
will it change the way cablers install the
National Broadband Network (NBN)?
G.Fast technology is similar to VDSL2
in terms of its application. It is capable
of a maximum downstream speed in
excess of 1Gbps on very short links
by using more than 100MHz of cable-
pair bandwidth and advanced
crosstalk cancellation.
At a reach of 250m, maximum speed
drops to about 150Mbps.
Reportedly, the technology will:
>
Make gigabit-level aggregate bit rates
possible by adding spectrum to copper
lines. The technology is equivalent
to adding extra lanes to a highway.
Current VDSL2 lines use spectrum up to
17MHz. G.Fast widens this spectrum to
106MHz. Anticipated amendments will
use frequencies up to 212MHz and take
bit rates to 1Gbps and beyond. Current
lab test have achieved 967Mbps on
20m of copper wire.
>
Provide fibre to the premises (FTTP)-
equivalent speeds without the intrusive
nature of an FTTP rollout. The distance
between homes and the node, or last
mile, becomes far less important with
G.Fast as it is able to achieve higher
network speeds over longer copper
line distances.
>
Be used in conjunction with the fibre
to the basement (FTTB), fibre to the
distribution point (FTTdP) and fibre to
the node (FTTN) rollouts under the nbn.
The trial, which was conducted in
Carlton, Melbourne, achieved speeds of
over 600Mbps over 100m of existing
copper wire.
Announcing the results of the trial at
the Broadband World Forum in London,
Tony Cross, the chief architect of the
nbn, says G.Fast offers tremendous
flexibility in delivering very fast
speeds to end users in a wide range of
different environments.
“nbn has been trialling exciting new
broadband technology, G.Fast, which
delivers lightning-fast speeds over
existing copper lines,” he says.
“We have achieved fantastic trial
speeds of more than 600Mbps on a
100m stretch of Category 3 copper cable
that is more than 20 years old – this is
more than five times faster than the
maximum speeds most of our FTTP end
users currently receive.
“In fact, had we not reduced the
frequency band used in the trial to avoid
affecting other broadband services
being delivered over the other copper
lines, our trial speeds could have reached
around 800Mbps.
“We have also been trialling G.Fast in
our national test facility in Melbourne
NEW TECHNOLOGY COULD
ACCELERATE THE ROLLOUT OF
THE NBN AS WELL AS THE SPEED
OF EXISTING COPPER NETWORKS.
PAUL SKELTON
EXPLAINS.
Current VDSL2 lines use spectrum up to 17MHz. G.Fast widens this spectrum to 106MHz. Anticipated amendments will use
frequencies up to 212MHz and take bit rates to 1Gbps and beyond.
COVER STORY: G.FAST