Stay up to date with all of ADTRAN's news, products and services with posts from the leaders in our industry.



Stay up to date with all of ADTRAN's news, products and services with posts from the leaders in our industry.


This is the third and final installment to my blog series regarding an enhanced DSL technology known as Frequency Division Vectoring (FDV). This technology and other super-vectoring technologies are being looked at by operators to once again allow them to leverage billions of dollars (or euros) of investment in their Fiber-to-the-Cabinet, -Node and -Curb deployments.  

These super-vectoring technologies can double the performance of today’s vectored VDSL2 supplying up to 300Mbps of broadband service. This allows operators to stave off both the Cable/MSO competition as well as the high cost associated with full blown Fiber-to-the-Home (FTTH) deployments.

Now that we’ve looked at some of the challenges in the market and the DSL acceleration technologies that have emerged to address those challenges, today we’ll explore what this means for service providers and the business opportunities ahead. Before getting into the operational benefits of deploying FTTx advancements, whether deployed in lieu of or in conjunction with a full FTTH deployment strategy, we will look at the market drivers for expanding premium broadband.

Today, in North America at least, the average peak demand for a residential broadband connection is approaching 50Mbps. At first glance, this seems hardly worthy of an investment in FTTH or these innovative 300Mbps FTTx technologies.  However, with disruptive cable operators investing in Gigabit service supporting networks via DOCSIS 3.1, and other disruptive new service provider entrants expanding their FTTH footprint, there is a need to compete with headline speeds. Many consumers simply pick the higher rate when comparing a similarly priced offer.

Emerging consumer applications– as always– will drive the demand for bandwidth and operators have to be ready to deliver or risk being marginalized by the market and competition. Cloud-based home backup and Ultra HD (4KTV) are poised to push the bandwidth demand to 100 Mbps or more per home in the next few years. The shift to cloud services, mobile broadband expansion, the growth of Internet of Things and the demand for community development all play a part in moving the needle.

Great for Central Europe, not so much for North America

To understand the business case advantages offered by these new FTTx technologies, we need to understand an important FTTx metric – copper loop length. This provides an important indicator of which geographic regions and which residential markets would be in favor of FDV and therefore most likely to champion the industry standardization and network homologation of such technologies.

There are longer FTTx loop lengths deployed in North America, whereas in central Europe they generally have deployed their services cabinets much closer to the customer, many of which fall into the loop length ranges that could take advantage of super-vectoring service rate gains. As a proof point, since I last wrote on this topic in December, there has been an ITU-T standards meeting in Geneva where European incumbent operator DT was proposing to create a new annex for enhanced data rates compatible with today’s VDSL2 17a services deployed in Europe today.

It is important to note that for any super-vectoring technology to be usable, whether FDV or another, it must be standardized and available from all of an operator’s vendors; must be deployable into existing cabinets and must run in parallel with the existing vectored VDSL2 services. Of course, the technology must also improve upon the performance of today’s vectored VDSL2 service rates at intermediate FTTx copper loop lengths, generally 200 – 400m from the customer. This loop length is too far for typical FTTdp/ deployment scenarios but much closer than 500 – 700m distances…perfect for vectored VDSL2. Super-vectoring is all about squeezing more bandwidth out of these shorter copper loop lengths sitting in no-mans-land – too long for FTTdp and too short for vectored VDSL to take advantage of.

The Overall Cost to Pull Fiber

How committed a service provider is to their large investment in FTTN/Cab comes down to the cost of the alternative which is pulling fiber down or across the street, through a yard or wall and throughout a residence.  This cost is what is saved by leveraging next generation DSL technologies like FDV and as the premium bandwidth is already installed. New construction houses, condominiums and apartments, known as greenfield deployments, are strong targets for FTTH. We want to pull new fiber… not new copper. This means not just though the street but the building as well. This latter part has been a challenge as many new homes continue to be wired with CAT3 telephone wiring or 100Mbps CAT5/6 Ethernet cable. When service providers get involved in new residential development they plan for these new homes to be constructed with optical fiber through to the wall socket. Now what about the cost of upgrading existing homes with copper wiring to optical fiber?

The cost savings afforded by cabinet and distribution point FTTx deployments is based on the cost to pull fiber those last few hundred meters to and through the home. US$500 – 700 dollars per home is the range seen most often in published business cases. The cost to pull fiber can vary. It can be as low as $1 per ft ($3 per meter) when good quality duct and conduits exist, or it can cost a magnitude higher when boring is required. Boring can be required when ducts are full, do not exist or are in disrepair. This is the case for most homes over 20 years old and historic streets and buildings. North America has relatively newer buildings compared with Europe so lower FTTH connection costs generally apply. That said, according to the 2013 American Housing Survey from the US Census Bureau, the average residential dwelling was built in 1974. Less than 15% of homes are younger than 15 years old increasingly the likelihood of requiring higher priced techniques to connect homes with fiber.

Multi-dwelling units (MDU), apartments and condominiums house a large percentage of the population and offer a great opportunity to leverage existing fiber that often pass by these buildings. The cost to connect each suite can be costly and with 25% of the population living in MDUs and as high as 40% in many dense urban environments, MDUs must be a target for delivering premium broadband services. Leveraging FTTx technologies allow operators to quickly and cost effectively add subscribers. And unlike DSL technologies of the past, the existing phone wiring delivering broadband is owned and maintained by the landlord – not the incumbent telco allowing competitive service providers.

Super-vectoring as an accelerant to Fiber rollouts

DSL acceleration technologies have sometimes been criticized for taking resources away from – and ultimately delaying – the deployment of FTTH. and FTTdp has been the most recent target of that criticism. However, the prudent operator and careful observer of these technologies recognizes that when a FTTx solution can allow new bandwidth-intensive applications to be rolled out, this in turn drives demand for FTTH. FTTx deployment models allow operators to maximize fiber deployed in the street today allowing for an important return on that asset which raises monies to be later invested in FTTH.

In the same way super-vectoring should not detract from the momentum of other premium broadband deployment models like FTTdp and PON fueled FTTH. FDV meets this important requirement. FDV is aligned with the DSL technology roadmap. FDV leverages advances in chipset technology and is therefore synergistic with deployment plans being constructed by dozens of the world’s largest broadband network operators.

Super-vectoring technologies like FDV allow incumbent operators to deliver double the bandwidth currently deployable out of their existing cabinet infrastructure. Raising service rates from today’s 100 – 150Mbps up to 200 – 300Mbps. These rates provide important provider differentiation and in the case of FDV help accelerate the deployment of 500Mbps and greater FTTdp deployments by seeding components into the network.

As handheld and home devices and appliances become more powerful, more connected; As consumer and home automation applications become more cloud-based and more sophisticated, your residential broadband connection must become a high bandwidth, low latency cloud services conduit. FDV is another tool broadband network operators can use to meet this network performance objective.

Kurt Raaflaub leads ADTRAN’s strategic solutions marketing, and has more than 20 years’ experience in telecom. He has global solutions marketing responsibility for the areas of SDN/NFV, Gigabit Broadband, and Customer Connectivity directed at the residential, enterprise and backhaul markets. Prior to his current position, Raaflaub was responsible for directing ADTRAN’s Broadband, Carrier Ethernet and Packet Optical solutions marketing activities within ADTRAN’s Carrier Networks Division. In 2006, he joined ADTRAN from Nortel where for over a decade, he held various roles focused on marketing and managing new disruptive market opportunities.