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[kitz]

Stumbled across this from Alcatel-Lucent which enables "speeds of 300 Mb/s over two DSL lines at 400 meters".

In just five steps Alcatel-Lucent has been able to create significant bandwidth gains. As illustrated below, starting with two physical twisted pairs, Phantom Mode creates a third virtual pair on top of the two physical pairs. Next, vectoring cancels the noise (i.e., cross-talk) generated between the physical and virtual pairs. Finally, VDSL2 bonding combines the two physical pairs and the virtual pair into a single large pipe.

300 Mb/s over 2 pairs at 400 m – Bell Labs “Phantom Mode” innovative demo 300 Mb/s in 5 steps

[Black Sheep]

Nice find, Kitz ........ my own personal opinion is that this technology is probably impractical on a cost basis. It would mean providing more copper in the ground (as most DP's are at, or near, saturation), whereas putting fibre in the ground is a far cheaper solution.

However, it makes one think about what the pioneers of telephony might make of the true capabilities of Cu cable, were they alive today ?? Incredible science. 

[Ronski]

I notice they also show it using 0.6mm copper, not the more common 0.5mm.

[William Grimsley]

How do I enable "phantom mode" on my VDSL connection?

[loonylion]

How do I enable "phantom mode" on my VDSL connection?

you don't. You need 2 fttc lines plus the equipment at both ends needs to support it. Since it's experimental no equipment currently in use will support it.

[NewtronStar]

Plus the extra cost for another FTTC line + line rental and me being in a high priced area that would work out at £90 a month for two lines just to get 70Mbps with bonding 

[burakkucat]

It's nice to see that the techniques first used many years ago with telephony circuits are still found to be useful in the present day. 

[kitz]

Im sure we all get the bonding bit  & vectoring to bring a line up to 200Mbps - its the Phantom Mode that that is new.

There doesnt seem to be much information about how 2 x 100 Mbps lines becomes 3 x 100 Mbps.   
However, Ive just found this technical paper which basically states 3 signal paths can be created over 2 pairs.

http://www.hit.bme.hu/~jakab/edu/litr/Access/DSL/IEEE_06108362_phantom_mode.pdf

 

[kitz]

Plus the extra cost for another FTTC line + line rental and me being in a high priced area that would work out at £90 a month for two lines just to get 70Mbps with bonding 

Im sure weaver would be interested in this if it could be applied to ADSL.   
Quite a lot of businesses use bonding, so it has the potential to increase speeds for less £

In new DSL technologies, the phantom-mode signal, defined
between  two  pairs,  will  also  be  exploited  in  addition  to  the
conventional differential-mode signal on one pair. In this way,
three  signal  paths  can  be  defined  for  a  quad.  In  this  paper,
it has been shown that both the two differential-mode signals
and  the  phantom-mode  signal  are  eigenmodes  of  the  system.

Simulations also show that those three modes do not influence
each  other.  The  measurements  confirm  that  the  crosstalk  is
indeed very small between the different modes. However, it is
not negligible. Since the crosstalk is very small, this new tech-
nology will strongly increase the achievable capacity and con-
sequently support higher bandwidth applications. This increase
will be even much stronger when combining this technique with
vectoring.

[kitz]

It's nice to see that the techniques first used many years ago with telephony circuits are still found to be useful in the present day. 

ISDN ?

When looking for info about phantom mode and before finding the above white paper - I did see mention somewhere else saying that the technology wouldn't be wasted on copper and implying it could be used on fibre....   but Ive yet to fathom that one out.   

----
ETA

Whilst thinking about ISDN, made me ponder on this

It would mean providing more copper in the ground

.

What percentage of lines have 2 pairs going to the premises ?   So it would be an issue to the DPs?     

[burakkucat]

It's nice to see that the techniques first used many years ago with telephony circuits are still found to be useful in the present day. 

ISDN ?

Long, long before ISDN. Go way back to the days when the main (trunk) network consisted of amplified audio pairs (four wire circuits, quads, with a "Go" and a "Return" pair) with repeater stations every N miles. As long as the Go and Return pairs were balanced and equalised then a phantom pair could be implemented for signalling or other purposes.

The best description I can currently lay my paws upon is the Wikipedia entry for a phantom circuit.

I suspect that both 4candles and licquorice could tell us about PO Telecommunications repeater stations from the more recent past.

[S.Stephenson]

Ill have 2 lines soon and am under 400m from the cabinet can I break into the cabinet and set this up please...

[WWWombat]

I notice they also show it using 0.6mm copper, not the more common 0.5mm.

Looking at the language used by Alcatel, I think this idea stems from the early days of vectoring: 100Mbps at 400m on 0.6mm copper. Perhaps 2010? When Alcatel pushed on commercially, in 2012, they were happy to suggest 100Mbps at 500m, on 0.5mm.

I found another article, where they update the 2-pair+phantom speed to 390Mbps, and add a 3rd and 4th pair, plus phantom, plus phantom on phantom, to reach 900Mbps on the same 400m!
http://www.ospmag.com/issue/article/The-Copper-Phantom

Yes, 2010. The lack of mention of G.Fast also dates it:
https://www.alcatel-lucent.com/press/2010/002246

Nowadays, G.Fast gets the headlines. Who would bet that Alcatel-Lucent (should I call them Nokia) were using bonding and phantom techniques for XG.Fast?
http://www.zdnet.com/article/bell-labs-achieves-10gbps-broadband-speed-on-copper/

[gt94sss2]

Nowadays, G.Fast gets the headlines. Who would bet that Alcatel-Lucent (should I call them Nokia) were using bonding and phantom techniques for XG.Fast?

As you would expect, XG.Fast is also something BT have been playing with.

I believe the attached table dates back to 2014 though as ISP Review say:

NOTE: Take Alcatel-Lucent’s table with a pinch of salt because VDSL2 / FTTC lines can operator at distances of greater than 400 meters, with well above 1,000 meters being seen in the wild.. albeit naturally at much slower speeds.

[Black Sheep]

What percentage of lines have 2 pairs going to the premises ?   So it would be an issue to the DPs?

This is what I alluded to above, kitz ...... "Nice find, Kitz ........ my own personal opinion is that this technology is probably impractical on a cost basis. It would mean providing more copper in the ground (as most DP's are at, or near, saturation), whereas putting fibre in the ground is a far cheaper solution. 

I can't see this ever taking off on any kind of large scale, personally ??

[admin - fixed tags]