US Telcos Indifferent to G.Fast

Speed_Street_SignG.Fast is a new technology that can deliver a large swath of broadband over copper wires for a short distance. The technology uses some of the very high frequencies that can travel over copper, much in the same way that DSL does for lower frequencies.

The International Telecommunication Union (ITU) just approved the final standard for the technology with the G.9701 standard for “Fast Access to Subscriber Terminals.” Several vendors including Alcatel-Lucent and Huawei have been producing and testing units in various field trials.

British Telecom has done a number of these tests. The largest such test was started in August for 2,000 customers in Huntingdon, Cambridgeshire. During the trial they are offering customers speeds of 330 Mbps, but they expect at the end of the trial to be able to raise this to about 500 Mbps.

The technology involves building fiber along streets and then using the existing copper drops to bring the bandwidth into the home. This is the most affordable kind of fiber construction because a telco can overlash fiber onto its existing copper wires on the poles. That means very little make-ready work, no permits needed, and no impediments to quick construction. This kind of fiber construction can literally be done at half of the cost faced by other fiber overbuilders.

British Telecom has done a number of trials across the country. Alcatel-Lucent has also done trials with Telkom Austria. But for the most part American telcos have shown no interest in the technology. The only real trial here that I’ve read about is a trial with CenturyLink in Las Vegas.

And I frankly don’t understand the reluctance. G.Fast is a halfway solution on the way to a full fiber deployment. As cable companies and overbuilders like Google are stepping up deployment of gigabit speeds, either through fiber or through fast cable modems using DOCSIS 3.1, the telcos have been announcing fiber builds to remain competitive. AT&T has announced gigabit fiber builds in more than twenty markets. CenturyLink says it will be passing 700,000 homes with fiber in 2016.

So why wouldn’t an American telo seriously consider G.Fast? With capabilities up to 500 Mbps in real-world applications it gives them a product that can compete well with other fast technologies. And by overlashing the fiber to deploy G.Fast the telco will have tackled one of the major costs of building an FTTP network, by getting the fiber deep into the network. And with G.Fast a telco can avoid the expensive fiber drops and electronics which are the most expensive part of a FTTP network for them.

I could envision somebody like CenturyLink building fiber to the more lucrative parts of town while deploying G.Fast to older copper neighborhoods. This would give them a far greater fast broadband coverage, making it easier and more cost effective to advertise their broadband.

But it seems like most of the US telcos just want out of the copper business. And so, rather than take this as an opportunity to milk another decade out of their copper networks before finally building fiber, they seem prepared to cede even more broadband customers to the cable companies. That has me scratching my head. The cable companies have clearly accepted that their entire future is as ISPs and that data is the only real product that will matter in the future. It just seems that the large telcos have not quite yet come to this same conclusion.

Is There any Life Left in Copper?

RG-59 coaxial cable A: Plastic outer insulatio...

RG-59 coaxial cable A: Plastic outer insulation B: Copper-clad aluminium braid shield conductor C: Dielectric D: Central conductor (copper-clad steel) (Photo credit: Wikipedia)

Copper is still a very relevant technology today, and when looked at on a global scale nearly 2/3 of all broadband subscribers are still served by copper. That percentage is smaller in the US, but this country has a far more widely deployed cable TV system than most of the rest of the world.

The most widely deployed DSL technologies today are ADSL2 and VDSL. In theory these technologies can get speeds up to about 40 Mbps. But depending upon the gauge, the age and the condition of the copper many actual deployments are closer to 20 Mbps than the theoretical 40 Mbps.

ADSL2 and VDSL technology has been widely deployed by AT&T in its U-verse product which serves over 7 million data customers and over 4.5 million cable customers. AT&T has made the product available to over 24 million homes. AT&T can support the product up to about 3,500 feet on good single copper pair and up to 5,500 feet using a two bonded copper pairs.

And ADSL2 is a pretty decent product. It can deliver IPTV and still support an okay data pipe. However, as the cable companies are finding ways to get more bandwidth out of their coaxial cable and as new companies are deploying fiber, these DSL technologies are going to again fall behind the competition.

So what is out there that might resurrect copper and make speeds faster than ADSL2? Not too long ago I wrote a blog about G.Fast, which is Alcatel-Lucent’s attempt to find a way to get more speeds out of legacy copper networks. In recent field tests ALU achieved a maximum speed of 1.1 Gbps over 70 meters and 800 Mbps over 100 meters for brand new copper. On older copper the speed dropped to 500 Mbps for 100 meters.

However, the G.Fast distance limitations are far shorter than ADSL2 and G.Fast is really more of a drop technology than a last mile technology and it would require a telco like AT&T to build a lot more fiber to get even closer to houses. You have to wonder of it makes any sense to rebuild the copper network to be able to get up to 500 Mbps out of copper when fiber could deliver many gigabits.

There are other technologies that have been announced for copper. Late last year Genesis Technical Systems announced a scheme to get 400 Mbps out of copper using a technology they are calling DSL Rings. This technology would somehow tie 2 to 15 homes into a ring and bridge them with copper. Details of how the technology works are still a little sketchy.

In 2011 the Chinese vendor Huawei announced a new technology that will push up to 1 gigabit for 100 meters. This sounds very similar to G.Fast and sounds like a way to use existing copper within a home rather than rewiring.

There is one new technology that is finally getting wider use which is bonded VDSL pairs that use vectoring. Vectoring is a noise cancellation technology that works in a way similar to how noise-cancelling headphones work to eliminate sound interference. Vectoring eliminates most of the noise between bonded pairs of copper. Alcatel-Lucent hit the market with bonded pair VDSL2 in late 2011 that can deliver up to 100 Mbps. However, in real deployment speeds are reported to be 50 Mbps to 60 Mbps on older copper. That is enough speed to probably give another decade to DSL, although to do so requires a full replacement of old technology DSL technology with VDSL2. One has to wonder how many times the telcos will keep upgrading their copper electronics to get a little more speed rather than taking the leap to fiber like Verizon did.

One only has to take a look at the growth rate of the data used at homes and ask how long copper can remain relevant. Within a few short decades we have moved from where homes could get by on dial-up and now find a 20 Mbps connection too slow. Looking just a few years forward we see the continued growth of video sharing and a lot of new traffic from cellular femtocells and the Internet of Things. It’s hard to think that it won’t be long until people are bemoaning the inadequacy of their 50 Mbps connections. But that day is coming and probably is not more than a decade away.

G.Fast

You are going to start hearing about a new technology that may infuse some life back into existing copper networks. The technology is being referred to as G.Fast. This technology promises to be able to deliver very fast speeds up to a gigabit over copper for very short distances.

Some are referring to G.Fast as a last mile technology, but it is really a drop technology. The distances supported by the technology are so short that this is going to require fiber to the curb, or as some are now calling it, fiber to the distribution point.

Alcatel-Lucent and Telekom Austria just announced a field trial of G.Fast. That trial achieved a maximum speed of 1.1 Gbps over 70 meters and 800 Mbps over 100 meters for brand new copper. On older copper the speed dropped to 500 Mbps for 100 meters.

Current copper technologies use only a small portion of the theoretical bandwidth available on a copper wire. For example, most VDSL2 systems deployed today use up to 17 MHz of spectrum on the copper. G.Fast can provide more speeds by using more of the available spectrum and will be able to use somewhere between 70-140 MHz on copper. Plus G.Fast will be more efficient. Today DSL functions by dividing the data path into sub channels which each contain about 15 bits of data. Engineers are looking at coding and modulation techniques that will increase the bits per sub channel for G.Fast and thus increase speeds more.

G.Fast also will benefit by an existing technique called vectoring. This technology is used today with VDSL2 and eliminates crosstalk interference between copper pairs. It does this by monitoring the noise on copper and then creating an anti-noise signal which cancels the noise in the same was as is done by noise-canceling headphones.

Right now Alcatel-Lucent is spending a lot of time on G.Fast because they see a big opportunity to make more money out of the old copper networks. So let’s look at the issues that a large telco like AT&T will face when considering the technology:

  • Because the distances to deploy G.Fast are so short, the carrier is going to have to build fiber past every customer, just like in a FTTH network. A large carrier like AT&T has some advantages over a fiber overbuilder in that they can overlash fiber onto existing copper on pole lines. This is cheaper and faster than putting up fiber for a new provider who has to deal with pole make-ready costs.
  • Copper drops are generally the worst copper in the network. These wires get banged around by wind and suffer from repetitive water damage and are the weak point in the copper network. The promised savings from G.Fast is to lower the cost of installation at a customer. Some of this savings disappears if too many homes need a new drop to make it work.
  • G.Fast will save the cost of getting into the house. Once connected to an existing telephone NID on the outside of the house the signal can go anywhere in the home that is already wired for telephone. But the distance issue quickly kicks in and I would expect carriers to take this to a wireless right inside the house.
  • Savings are going to depend on how inexpensive the G.Fast electronics are compared to FTTH electronics.
  • Large telcos have relied for years upon customer self-installation of DSL and they will need G.Fast to work the same way.

So the savings to somebody like AT&T come from a) cheaper fiber installation costs because of the ability to overlash, 2) the ability in many cases to use existing drop and inside telephone wires, and 3) the ability to have customers self-install the product to avoid having to go into the home.

There are still a lot of technical issues to consider and overcome. Some issues that come to my mind include things like overcoming existing splices in the copper, and making sure there is no interference with existing DSL.

The expected time line for the deployment of G.Fast is as follows:

  • Standards finalized by spring of 2014.
  • Chip sets developed in 2015.
  • First generation hardware available in 2016 that probably won’t support vectoring.
  • Mature second generation equipment available in 2017.

Since a carrier has to build fiber everywhere for this to work, the technology is really competing against FTTH. By the time this is readily available there may be lower-cost units for FTTH deployment and I think any carrier would prefer an all-fiber network if possible.