ITU Says MGfast Standard Can Do 8Gbps Broadband via Copper Lines
Openreach (BT) might have shelved the use of hybrid fibre G.fast (ITU G.9701) broadband technology in the UK, but the International Telecommunication Union (ITU) has continued to develop a sequel to that technology called MGfast (G.9711) and it will soon become more widely available, with speeds of up to 8Gbps being promised.
We first reported on some early research into MGFast (G.mgfast) technology in 2017 (here), which is back when G.fast was still very much something that Openreach intended to deploy at scale – aiming to reach around 10 million UK homes and businesses by the end of 2020. This came just before the Government started pushing for “gigabit” and “full fibre” deployments.
Openreach’s implementation of G.fast was much like their prior Fibre-to-the-Cabinet (FTTC / VDSL2) technology, which is to say that it worked by running an optical fibre cable to a local street cabinet or remote node, which then served local homes over the final run of existing copper cable. But while FTTC / VDSL2 promised top speeds of up to 80Mbps, G.fast – at least in the UK – could offer up to 330Mbps.
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The catch is that in order to attain such speeds the first generation of G.fast services needed to harness much more spectrum frequency (e.g. 106MHz vs c.17MHz on VDSL2), as well as various other improvements (e.g. vectoring by default). This meant that – due to signal degradation over distance – you had to live much.. closer to your local PCP street cabinet in order to get the best speeds (excluding a big chunk of the market).
In theory, G.fast could deliver top theoretical speeds of up to 1-2Gbps, but to get that you’d have to be just a few tens of metres away (i.e. much more expensive to deploy and maintain).
Enter MGfast
By now you’ve probably already guessed that MGfast, while claiming to offer much improved top speeds of up to 8Gbps (aggregated) via 424MHz of spectrum frequency in Full Duplex (FDX) mode – or 4Gbps when in Time Division Duplexing (TDD) mode, also carries with it a much bigger caveat on distance.
Suffice to say, you’d need to be almost sitting on top of the distribution node to really benefit from this, and that’s before we consider that a future version of MGfast may expand the frequency band to 848MHz for even higher bit rates (i.e. over even shorter distances). Previously, there was talk of 848MHz being used to hit 10Gbps.
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The distance issue is partly why the ITU are now pitching this more for Fibre-to-the-extension-point (FTTep) or Fibre-to-the-Building (FTTB) style deployments. In this scenario you might run MGfast from the bottom of an apartment block (MDU), or similar building (office etc.), and would then be more likely to use existing coaxial cable or CAT5/6-type Ethernet wiring to reach individual homes/flats.
Admittedly, this could also work over thin twisted-pair copper wires, like the ones that Openreach are in the slow process of now retiring, but you probably wouldn’t want to waste your time with that.
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ITU Statement
The MGfast standard, ITU G.9711, not only promises higher bit rates than ever, but also ultra-low latency for highly interactive applications, the capability to optimize Quality of Service (QoS) in line with the needs of different applications, and point-to-multipoint operation enabling better coverage within the premises … [as well as] introducing advanced forward error correction based on Low-Density Parity-Check coded modulation
Ultimately, MGfast is now an approved standard (since April 2021), but we’re unlikely to ever see it forming the backbone of any major deployments in the UK, which brings us back to G.fast.
As for the story of G.fast in the United Kingdom, the technology only ever reached around 2.8 million premises and its performance often struggled to deliver on what was advertised, while take-up continues to be weak. Little wonder that Openreach ended up shelving it in favour of a much more future-proof approach via Fibre-to-the-Premises (FTTP) technology, which is planned to reach 25 million premises by December 2026.
It’s fun to see the ITU talking about MGfast now and a market for that may still exist somewhere, but the reality is you’re unlikely to ever see it doing much in the UK, and that’s just fine.
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he also founded ISPreview in 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on X (Twitter), Mastodon, Facebook, BlueSky, Threads.net and Linkedin.
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I wonder, as PSTN & ADSL services are withdrawn in FTTC areas, will OpenReach try redeploying the lower frequencies to bolster VDSL performance? Perhaps it is too much hassle and will be overtaken by the speed of the FTTP roll-out? We can hope.
I personally think I would be cheaper to deploy FTTP yes it’s expensive to lay from the street to people homes. But For deploy MGFAST now they would be wasting money. FTTP is future proof.
Technically they could already do that with some spectrum management approaches in non-ADSL areas (e.g. the Long Reach VDSL trials). But going higher than c.17MHz is more problematic and creates compatibility issues, such as with some end-user CPE and street cabinets on older or SLU kit. So I doubt you’ll see the 35MHz profile for FTTC, but you never know. However, right now, spending to upgrade all of that to FTTP is the direction of travel, so anything else would distract resources from that.
they can’t.
DSL prohibits frequencies below 4Khz.
It would add a couple tones to the US0 band, increasing upstream by a fraction of a Mb.
It isn’t supported by the standards and it wouldn’t be worth the hassle for a very tiny gain in upstream.
That was specifically talking about the PSTN voice tones.
I missed the bit about ADSL.
They already use the ADSL tones on VDSL2 in the UK.
They simply cut the VDSL2 power back to prevent interference with existing ADSL.
The further from the exchange a cabinet is, the weaker the ADSL power/signal is, therefore the more they cut back the VDSL2 power.
If ADSL was turned off then increasing the VDSL2 power for the ADSL tones would provide a benefit, but I don’t think they are currently planning on turning off ADSL before VDSL.
gah give it up. remember when GFast was going to save the day? and what an utter flop it was apart from anyone who could throw a stone at their local green cabinet.
Has other deployment scenarios besides Openreach’s disastrous FTTC/N deployment.
A few uses for this but they are very few.
Onwards to FTTP for the other 99%.
Seem MGfast are a waste of time (only benefit to shortern line length <100m
https://www.semanticscholar.org/paper/MGFAST%3A-A-New-Generation-of-Copper-Broadband-Access-Oksman-Strobel/aea1072b08cb9c7c42d8ae008681ec71bc822b16
Don’t remind me MGfast please!
Crud don’t tell the Australian NBN this.
I mean it could work for their Fibre to the Curb deployments but yes it should be Full Fibre or bust!
What… government got it right pushing for FTTP, nah don’t tel me so, As Victor Meldrew said “I don’t believe it”
No thank you, FTTP or bust.
Jesus, just let copper die already! Why are they wasting so much time and research in whateverDSL/FAST when fibre is becoming the “de facto” standard infrastructure pretty much everywhere?
..because it’s not the de facto standard everywhere (yet) and there are still some niche deployment scenarios where MGfast might find relevance.
Not forgetting that Virgins network to the premiss is still copper (co-ax) and that works just fine at 1Gbps+
Not the same technology (3.1 been rolled out) and cable type
VDSL is pushing distance speed limited speeds over 50 year old cables
Virgin’s network could go up to 10Gbit/s download and 6Gbit/s upload if they upgraded it to DOCSIS 4.0
https://en.wikipedia.org/wiki/DOCSIS
I could never work out why FTTC was never implemented using 4 wire?
Vast majority of houses have multi-pair drops, so it’s not like the last-legg needed to be replaced, and a 4 wire modem setup would have hugely increased the available bandwidth
More expensive modems required in homes and more ports required in cabinets.
Really?
And no more ports required (have you ever looked inside a DSLAM?)
Yes.
DSL bonding (using 4 wire/2 pair) uses double the number of VDSL2 line card ports.
In a binding group you have a primary port and member ports.
‘And no more ports required (have you ever looked inside a DSLAM?)’
Yes, a large Huawei. Uses 2 x 64 pin champ connectors for each 64 port line card – a pin for each wire in each pair. Physically can’t connect more than 64 pairs to each card so to run 64 x 2 pair would fill 2 cards, 64 x 1 pair a single card.
CPE more expensive as you need 2 sets of DSL chipsets from the 2 connectors on the back through the modem. It’s not some elegant thing using its own connectors, it’s 2 x standard 2 pin either side.
Just for my own curiosity Simon, What made you think you could just connect 2 pairs to each line card port?
Flogging a dead horse I think. FTTP is the future
for this speed to be achieved would Openreach need to install a cabinet in my living room next to my router
Tower blocks are a good example of the niches that may apply to. It may be easier to install a ‘cabinet’ in the basement and run up the building on existing copper. Fibre is always preferred, but if it is too expensive/impractical this may provide an answer. I suspect Openreach have enough to keep them busy with FTTP, such systems may be sold directly to landlords to add value to the properties within.
They just use FTTB (ethernet ports to each room from a main fibre cabinet on the ground floor)
FTTB is an acronym, not a technology.
G.Fast can be deployed as FTTB.
What exactly do you mean by FTTB?
When you say Ethernet ports I’m assuming you mean using Cat5e or Cat6 and GbE to each apartment?
Mick is talking about buildings with no Cat5e/Cat6 installed where the building owner isn’t willing to sign a wayleave to allow wiring to be installed.
You may as well do FTTP if you get a wayleave to install to each apartment.
What technology do they use to deploy FTTB when there’s only twisted pair throughout the building?
That’s where G.Fast or MGFast can be used.
John how about the landlords stop being tightwads and fit cat6 in the flats down to the basement instead of going through all the trouble of FTTB and then duct taping GFast/whatever in over crummy old twisted pair POTS? Makes no sense to me, ooh but we’ll some miniscule amount. wow.
If you’re going to the trouble of running a feed to every flat why on Earth would you use copper at all.
I’m not sticking up for landlords.
I’d happily see legislation forcing all landlords to accept at least 1 gigabit capable provider who have a wholesale offering, providing all tenants a choice of gigabit provider.
Until then, for anyone in an MDU with nothing but a twisted pair to each apartment and with a stubborn landlord or logistics preventing an install, a small DSLAM could provide multi gig broadband.
Who’d have thought thick chunky copper cable was capable of so much???? erm…everyone.