True to its word that it will become an IP specialist, taking Cisco on, head-on, Alcatel-Lucent is turning up the heat on G.Fast trials. Telcos in the US and Europe have had to take a back seat as cable companies have dominated headlines in broadband provision, always claiming the top spot in terms of broadband speeds. Perhaps not for much longer.
Now Alcatel has a trial on live Telco lines at Telekom Austria, which are in a traditional wire bundle, using G.Fast and operating at speeds over 1 Gbps, indicating that G.Fast will be ready and waiting shortly after or even before DOCSIS 3.1 delivers even higher speeds for cable companies.
What this disguises is the level of investment that Telcos need to continually pay out in order to get there. Cable companies are charged simply with replacing their DOCSIS modems and Cable Modem Termination Systems (CMTS) to move up to DOCSIS 3.0, and then once again to 3.1, but Telcos have to physically fiber closer to each home, which means digging up the roads and either re-siting every cabinet they own or placing a new class of smaller box closer to homes, which handle the transition from fiber to G.Fast. They also have the same replacement costs of the CPE and termination systems that cable has.
The next DOCSIS version is called 3.1 and its target is to offer 10 Gbps down and 1 Gbps up. The specification, like G.Fast, is still being developed. Two technologies which are widely used in other markets especially radio are OFDM and LDPC a form of Forward error correction, and these are at the heart of DOCSIS 3.1 design. Installations are not expected until 2015 and full scale deployment will be phased in over a four or five year period from then. This then has to be the G.Fast delivery date, and Alcatel suddenly makes it look like Telcos can achieve this or beat it by a year.
DOCSIS 3.1 expected schedule is to make silicon available sometime in 2014 and put these into devices and start to test and deploy them during 2015 . Both sides, suppliers for cable and suppliers for telcos, are likely to go through acceleration, as both sides are eager to claim the top speed spot in broadband.
Cable clearly has the cost edge. DOCSIS 3.1 is being designed to fit into the DOCSIS 3.0 cabinets as blades, and for an ASIC (application specific integrated circuit) to be refreshed at both ends, so that production lines can just switch to new chips and carry on for both modems and CMTS blades. Cable won’t have to dig up the pavement for this upgrade, and more than likely, Telcos will, so it’s important that telcos get a little head start, and that’s what Alcatel is after here.
Alcatel has shown the technology working with A1, the subsidiary of Telekom Austria, and it is showing it in a non-standard form, a version designed by its Bell Labs which uses existing vectoring technology, but with fiber as close as 100 meters from the home.
Alcatel-Lucent is already claiming to be upgrading some 40 operators to VDSL2 networks using vectoring, offering telcos 100 Mbps speeds and in some cases 200 Mbps using bonding, without moving existing cabinets too much closer to the home.
But in G.Fast, in recent demonstrations and under laboratory conditions, Alcatel-Lucent achieved 1.3 Gbps over 70 meters, it claims, but that was without using vectoring. Now it has tried out some live homes using existing vectoring to cancel cross talk that comes from multiple wires being in the same binder.
The trial first tested G.Fast over a single, good quality cable, achieving a maximum speed of 1.1 Gbps over 70 meters and then 800 Mbps over 100 meters. On older unshielded cables, typical of most in-building cabling in Austria, the trial achieved speeds of 500 Mbps over 100 meters on a single line. However, when a second line was introduced, creating crosstalk between the two, the G.fast speed fell to only 60 Mbps and this is where the vectoring came in.
Once the vectoring was switched on, it removed the crosstalk and brought the trial speed back up to 500 Mbps over 100 meters. If Alcatel can get this working effectively, there is a chance that the last step of taking fiber right into the home, may never be necessary. Fiber-to-the-home services typically range from 100 Mbps to 1 Gbps as of now.
Alcatel insists that G.fast, is not yet standardized, and is still a long way off, but this type of demonstration is vital to push the standards committee in the direction Alcatel wants. Our guess is that this has to be done and dusted and ready for telcos to plan their implementation in mid-2014, so that Telcos can shorten their copper ducts reliably in time for a 2015 deployment.
Alcatel makes the point that any telcos that don’t want to wait, can shorten its copper and use VDSL2 plus vectoring and still get speed gains while it waits for the full G.Fast standard. Alcatel holds out the hope that it could deliver several hundreds of Mbps up to more than 1 Gbps over short distances in this way.