New technology could accelerate the rollout of the NBN as well as the speed of existing cable networks. Paul Skelton explains.

In 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 VDLS2 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 hit 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 and have achieved fantastic trial speeds of nearly 970Mbps over a stretch of 20m copper cable – so, the potential is huge.”

According to fixed broadband analyst firm Point Topic’s chief executive, Oliver Johnson, many leading markets will adopt G.Fast in the next five years, with coverage in some mature countries potentially approaching 50%.

“G.Fast is a vital technology for operators with copper in their networks,” he says.

A new Point Topic report revealed that at least 100 million people are expected to be subscribed to gigabit labelled services by 2020. Between now and then, the Compound Annual Growth Rate (CAGR) of subscribers to gigabit tariffs is projected to be at least 65%.

Close to 70% percent of growth is expected to come from the APAC region.

“G.Fast clearly works best economically in a mature market with copper in the local loop so I expect most of today’s leading markets will have some G.Fast in the next five years and some should see coverage approaching 50% of the market,” he says.

The report shows there are currently less than 10 million subscriptions on a gigabit connection but predicts that is set to change with more gigabit tariffs on the market than ever before and the cost of services dropping.

Broadband Forum CEO Robin Mersh said operators should take the picture painted by Point Topic as a clear call to action to consider G.Fast deployments in their networks, and to use Broadband Forum standards and certifications, such as the newly developed YANG management models for FTTdp equipment and the interoperability testing program for G.Fast devices.

“The rate of growth predicted by Point Topic’s latest figures shows the scale of the issue the broadband industry is facing and why adopting key enabling technologies for ultra-fast access is so important,” he says.

“The growing trend of gigabit services points to the fact that more and more people want to use next-generation services, like 4K video, location-based services, security, home automation, video sharing, gaming and home office collaboration. G.Fast is how operators with copper in their networks can still enable all these things.”

But, it would appear, not everybody is a fan of the new technology, or at least of the nbn’s plans to incorporate it into its product mix.

In a blog post, telecommunications analyst Paul Budde has described the technology as “more hype than reality.”

“Part of the problem is that the technology uses a much larger frequency range of signal processing bandwidth than other copper technologies over a much shorter copper length. Some of these overlap those used by commercial VDSL, so running both technologies together causes interference,” he says.

“Another problem is the extra power supply that is needed for the nodes that need to be deployed within this technology.”
While this can all be resolved, it only adds further to the complexity of the already multi-technology mix that the company is using for the rollout of the NBN, he says.

“Further trials are planned for 2016. Technically they expect to be ready for commercial launches in 2017, but if they then decide to use the technology extensively it will take many years to move it into residential markets – basically another rollout, with all the associated costs attached.

“This development also depends on the availability of commercially priced hardware needed, to make sure such a rollout is indeed cost-effective. Currently it seems most likely that it will be a business product offering rather than a residential one.

“The question raised by all these band aid solutions is whether the end result will be better and cheaper than the original ‘do it once, do it good’ FttH approach.”

It’s clear that as far as Tony Cross is concerned, the positives far outweigh any potential downside.

In a blog he wrote on the nbn’s website, he said: “One of the things that most excites us about G.Fast is the flexibility that it gives us.”

“We could deploy it in apartment buildings by simply installing new equipment into the basement. We could supply a group of houses via a FTTdP model or even just a single premises if need be. There are numerous options. G.Fast really allows us to remove the need to actually enter premises to deliver ultra-fast speeds.

“The other great thing about G.Fast is that it solves a couple of real headaches.

“Firstly, with G.Fast we think retail service providers could offer end users a range of product plans, including symmetrical speeds of, for example, 300Mbps download and upload, something that would hold great value for commercial end users who wanted to have access to extremely fast upload speeds.

“Secondly, G.Fast would allow us to deliver ultra-fast speeds without actually needing to enter people’s homes – something that enables a much smoother rollout and is far more convenient for end users.

“If all goes well, we are looking to be able to launch G.Fast in around 2017 so over the next couple of years we will be learning as much as we possibly can from our global counterparts as we strive to bring fast broadband to Australians.”

For cablers, the best part is that the new technology won’t hamper your potential to make money from the rollout. Cable still needs to be pulled all the way into the building – you’re just saving yourself the hassle of running cable over the last mile.