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DSL/vectoring/G.fast

Bell Labs Claims Copper Speed Record

Bell Labs, the research unit of Alcatel-Lucent, is claiming to have achieved data transmission speeds of 10 Gbit/s over a 30-meters length of bonded copper using a technology it is calling XG-FAST. (See Alcatel-Lucent Claims Copper Speed Record.)

The tech is an extension of G.fast, an ITU emerging standard technology (soon to be finalized) that promises theoretical speeds of up to 1 Gbit/s over the copper connection to a broadband user's premises.

Bell Labs says it achieved the 10 Gbit/s speed using an XG-FAST prototype hooked up to copper lines provided by an unidentified European telco. The test also showed the potential of XG-FAST to enable 1Gbit/s symmetrical speeds over single copper lines at a range of up to 70 meters. The Alcatel-Lucent (NYSE: ALU) unit says XG-FAST uses a frequency range of up to 500MHz, compared with the 106 MHz to be used by G.fast deployments.

Table 1: G.fast vs. XG-FAST Technology Comparison

Technology Frequency Maximum aggregate speed Maximum distance
VDSL2* 17MHz 150 Mbit/s 400 meters
G.fast phase 1* 106MHz 700 Mbit/s 100 meters
G.fast phase 2* 212MHz 1.25 Gbit/s 70 meters
Bell Labs XG-FAST** 350MHz 2 Gbit/s (1 Gbit/s symmetrical) 70 meters
Bell Labs XG-FAST with bonding *** 500MHz 10 Gbit/s (two pairs) 30 meters
Source: Alcatel-Lucent
* Industry standard specifications. G.fast allows for upload and download speeds to be configured by the operator.
** In a laboratory, reproducing real-world conditions of distance and copper quality.
*** Laboratory conditions.

Why this matters
The further development of technologies that enable faster broadband speeds over copper is increasingly important to network operators with installed, dense copper access networks (including many, but not all, major European markets).

That's because a major chunk of the cost of deploying fiber-to-the-home (FTTH) broadband is running the fiber into homes and offices from street cabinets and other local aggregation points. Being able to take fiber close to end users and then be able to offer very fast fixed broadband services using existing sunk copper lines is extremely attractive, as it is cheaper and quicker and extends the useful life of the copper plant. (See No Easy Answers on FTTH Investment.)

While FTTH continues to be deployed around the world, the rate of deployment and uptake is relatively slow in most markets, providing a business opportunity for vendors that can boost copper broadband speeds. Alcatel-Lucent is now in a race with rivals such as Huawei Technologies Co. Ltd. to bring to market technologies that can help service providers deliver Gigabit broadband without having to take fiber plant all the way to the users' premises. (See BT Trials Huawei's G.fast for FTTx.)

— Ray Le Maistre, Circle me on Google+ Follow me on TwitterVisit my LinkedIn profile, Editor-in-Chief, Light Reading

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smhui 7/14/2014 | 9:22:17 PM
Re: Without Vectoring? Vectoring doesn't contribute much in the case of using only a couple of copper pairs especially for the last 30+ meters.
MMQoS 7/11/2014 | 7:47:03 PM
Re: The real broadband race Brook and mhhf1ve, are both correct about actual field speeds vs lab trial speeds.  I attended some of those ITU-T SG15/4 meetings where DSL equipment vendors promised BOC's higher speeds on copper based on improved signalling algorhythms and better chips.  In many cases those speeds were attained in their lab tests.

But installed copper wire, in most residential areas installed to support low speed voice communications, has properties different from the data grade copper TP used for these speed tests.  In addition, copper is an active element and is subject to change with age.

When we started the Metro Ethernet Forum, we did some testing of copper for Gig Enet in the metro and soon dropper it as the variation in the properties of installed copper was to great.  Pair bonding looked attractive too but then finding both ends of multiple pairs can be a real nighmare.

Now testing equipment exists which can measure the characteristics on a spot basis but then as mentioned earlier, rain, temperature and animals can all have a deleterious effect on the copper's characteristics over time.

Ants aside (corner case) fiber is the last mile answer especially with the speeds needed for 4K video.

MMQoS

  
Jahangir04 7/10/2014 | 11:33:33 AM
Without Vectoring? Another breakthrough for very short loops. Without Vectoring, such speeds or even close will not be possible in real world.
brookseven 7/10/2014 | 1:07:09 AM
Re: Another option R Clark,

The only way a copper solution makes sense is if you don't have to do refurb.  Putting in new copper today is potentially the stupidist decision that anyone could make.  The question really is what percentage of rehab do you have to do.  Beyond a very low percentage, you should just rip out the copper - put in fiber - sell the copper you pulled out.

seven

 
R Clark 7/9/2014 | 11:18:52 PM
Another option Good points made about the problems of legacy copper in ageing ducts, but you are going to have to refurbish the ducts for fibre anyway. Even if you can get say, just 1Gbps over 70m of copper as is suggested here that's a viable and significant advance on today without the cost of deploying fibre.

This gives operators another cost/performance option they can weigh against fibre and wireless.

 
mhhf1ve 7/9/2014 | 6:57:16 PM
Re: The real broadband race Lab speed records are generally not completely transferrable to the real world -- for a variety of reasons. Ethernet over copper speeds in various lab speed records have not translated to the real world, largely due to the varying quality of copper lines.
brookseven 7/9/2014 | 2:50:16 PM
Re: The real broadband race That's a good one.

True story here:  One of our first FiOS test installations was at a Verizon employee in Penn.  She had an ariel drop through a tree.  We had a bug in the time adjustment algorithm and it got triggered when the wind blew and put stress on the cable.

Also, there were installers who did a bad job at the fiber junction box and heavy rain would fill the box and push the poorly seated connectors out of correct alignment.

seven

 
Ryan Welch 7/9/2014 | 2:13:29 PM
Re: The real broadband race @Seven

Apparently fiber is also susecptible to insect infestation: http://www.fiercetelecom.com/story/verizon-fios-users-service-interrupted-ant-infestation/2014-06-26

You bring up a very good point about service quality. While the initial results are promising, further testing is certainly warrented.
Ariella 7/9/2014 | 1:10:24 PM
Re: The real broadband race @seven thanks for sharing. It's interesting how weather can affect phone quality through a whole chain of events like that. 
mendyk 7/9/2014 | 1:02:03 PM
Re: The real broadband race Agreed. This is something like developing a musket with a longer firing range. It's still a musket.
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