UPD BT Confirm UK Trial Areas for Superfast Broadband FTTC Vectoring Tech

BTOpenreach has confirmed to ISPreview.co.uk that the first locations to trial its FTTC (VDSL2) Vectoring (ITU-T G.993.5) technology in the United Kingdom, which could eventually help ISPs to deliver download speeds of up to 200Mbps (Megabits), will take place in Barnet (London) and Braintree (Essex) in England.

Vectoring technology can work in a single copper pair and is designed to remove interference (crosstalk) from the line by using a similar method of “noise cancellation” to some modern headphones. Otherwise speeds become slower as you get further and further away from your local street cabinet (FTTC only takes a fibre optic cable as far as this cabinet and then uses the existing copper line to reach your home) .

It is essentially a mathematical process that “calculates the interference between all pairs in a binder, based on the actual signals, and will use this information to generate a noise cancellation signal on each pair“.

But according to BT’s Head of Access Platform Innovation, Kevin Foster, the technology will be used more as a “speed enabler” than a speed booster. In other words headline speeds, which currently stand at 80Mbps for FTTC (though another rise to 100Mbps+ is anticipated), are likely to stay the same but those on longer copper lines could get faster speeds than they do today.

Kevin Foster revealed the information during his speech at the DSL Conference in Paris (France) and ISPreview.co.uk quickly moved to verify the development with Openreach. The operator revealed last week that it was planning to test the capabilities of Vectoring as part of a trial involving its CP customers during Summer 2013 (here).

An Openreach Spokeswoman told ISPreview.co.uk last week:

“It’s far too early to say whether we will be deploying vectoring in our network as any decision will be dependent upon the outcome of the trial.‪ However, we believe vectoring has the potential to be a cornerstone technology of FTTC deployment in the future.

Customer feedback and the latest figures from Ofcom suggest that our fibre products are performing very well and, as you would expect, we’re continually evaluating emerging technologies aimed at further enhancing performance.”

Sadly precise details about what implementation BT will be using remain unclear and Openreach will not reveal anything further until ISPs have been advised of its trial plans, which will take place sometime over the coming weeks. Vectoring will also cost money to deploy, although the investment is not expected to be too significant.

Estimates of what performance improvement we could expect to see tend to vary and there’s no accounting for the impact of a real-world environment. But with BT’s current 17MHz profile (17a) for FTTC it’s perhaps not unreasonable to expect that speeds of up to 100Mbps could be possible at up to 500 metres from the street cabinet, with up to 50Mbps being possible at around 900m and 40Mbps at up to 1200m (performance boosts of around 25% or more but very variable).

The performance could also be further increased by bonding several FTTC lines together, although that would be very expensive for home users. Similarly if BT were to increase FTTC’s spectrum allocation to 30MHz (possible but there are still some problems to overcome) then some estimates predict that download speeds of up to 200Mbps might be possible at distances of 300 metres from your cabinet.

In reality we’ll have to wait and see what the trials reveal before knowing what to actually expect and as usual the performance may be a lot lower than the best estimates.

UPDATE 26th June 2013

More details about the trial roll-out areas, dates and plan (here).