DSL Gets 'Base Stations'

While doing some research on how capacity will grow in fixed line and wireless networks in the future I stumbled over the following thing right in my neighborhood: Future bandwidth increases on the last mile to the subscriber come with an additional cost in comparison with today’s standard ADSL or ADSL2+ deployments because of extra hardware that has to be installed close the the subscriber.

For ADSL2+ the DSLAM is usually installed in the telephone exchange and the cable length to the subscriber can be up to 8 km for a 1 MBit/s service. For VDSL, which offers data rates of 50 MBit/s in downlink, the cable length must not exceed 500m. Thus, DSLAMs can no longer be only installed in central telephone exchanges but equipment has to be installed in cabinets on the street. The cabinets themselves are quite large (about half the size of a GSM or UMTS base station), require power, active cooling, and create noise. For the installation of the cabinets earthworks are necessary to lay the additional fiber and power cables required to backhaul the data traffic. The picture on the left shows a VDSL DSLAM cabinet that has been installed alongside a 'legacy' small telecom cabinet as part of the current VDSL build out in my region.

To connect a new subscriber a technician is required to manually rewire the customer’s line to one of the ports. Different sources currently specify the maximum capacity of such cabinets from about 50 to 120 VDSL ports. To support 500 VDSL connections per km², several cabinets are thus required. I wonder what happens when 5 different companies put such DSL 'base stations' in place!?

Comments

[Siegfried]

:-)
Indeed this technology has some potential in Germany where Deutsche Telekom is going for it.
Maybe a reason for DT to favour this is also the difficulty for them to upgrade the fiber-to-the-curb networks in eastern Germany.

Here in France, operators have more or less decided to skip VDSL and to go directly for FTTU. Which of course doesn't fundamentally change your issue of what will happen if several operators will put their networks in place: The discussion here is about how to share the fiber that has to be installed in the staircases of multi-tenant units (and, even before that, who will install, own, maintain, ... the fiber that goes from the street into each building and thus crosses the entry doors of the building... a "legal nightmare").

Looking at it from a non-German perspective, it somehow it reminds me of what happened with ISDN. I guess we will have once again a national solution in Germany...

[Niklas]

So VDSL is an incumbent only technology at least when installed in street cabinets since there will be maximum one more player allowed to install equipment at the street cabinet level. Once again we will have a monopoly, which will be a problem for everyone.