We’ve talked before about while Fiber is the end game for service providers around the world, depending on your location or geography, it may not be the most practical solution. As a result, we’ve seen advancements in DSL technologies over the last 10 to 15 years that have pushed the voice and data service launch point much closer to the customer and significantly boosted broadband speeds. The latest of these technologies, G.fast, will take this even further by delivering near Gigabit speeds over existing phone wiring. Practically speaking, however, what does this really mean? If I know FTTH access is where I need to get to, what will these technologies do to help me get there?
Getting more out of the Cabinet
Network operators have invested heavily in Fiber-to-the-Cabinet (FTTCab) construction in recent years, deploying as many as 10 – 20x cabinets for every central exchange they managed. This not only required the capital to construct these outside plant (OSP) DSL platforms, but there was also an investment in intellectual capital as well. Processes and procedures needed to be created and defined to turn up and maintain broadband services launched from these cabinets. In the end, there has been a lot of time, money and effort put into the infrastructure that no service provider will willingly or easily walk away from.
The new G.fast standard builds off the FTTCab investment that service providers have already made, but takes a different deployment approach. Due to the very short copper access lines needed to support very high service rates, the services launch point again moves closer to the customer but this time from the cabinet to the copper wiring distribution point (dp). The deployment strategy is known as Fiber-to-the-distribution point (FTTdp), and while it requires further investment before 500Mbps or more service rates can reach an area, the cost is still significantly less than a full blown FTTH access upgrade.
Something in between?
Frequency Division Vectoring (FDV) is a super-vectoring technology that allows incumbent telcos to once again go back to the well and squeeze more premium services supporting bandwidth out of their FTTCab deployments. Just like they have done for decades they will do what they have gotten pretty good at doing – add a new card to an existing street cabinet, send out a new low cost modem and keep customers by staving off cable and wireless service providers for another few years while they shore up their FTTH plans and budgets.
FDV can be used to double the vectored VDSL2 rate to deliver 200 – 300Mbps service rates and extend the service reach up to 40% further. It takes advantage of the shorter copper loops that are too short for VDSL2 vectoring technology to use to any meaningful effect, and are too long for G.fast technology to leverage. This is generally 200 – 400 meter copper loops. These shorter copper loops extended from more deeply deployed street cabinets are common in throughout Central Europe and makes a cabinet sitting in “no man’s land” a means to deliver premium broadband services.
Ultimately, FDV cleverly combines VDSL2 and G.fast to produce an improved performance. A performance that is near that of full spectrum G.fast, but is not handicapped by having to vacate the lower frequencies reserved for the previously deployed VDSSL2 services. This allows G.fast technology to be deployed in existing FTTCab installations rather than to-be-constructed-FTTdp-installations by removing the 80% – 90% performance tax levied by existing VDSL2 services.
Now that we’ve looked at some of the challenges in the market and the technologies that have emerged to address those challenges, in our next installment we’ll explore what this means for service providers and the business opportunities ahead.
Kurt Raaflaub, a 20-year telecom veteran, has global responsibility for directing ADTRAN’s carrier networks solutions marketing activities.