The superfast copper landscape

23.07.2014

Having proven 400 Mb/s over two copper pairs back in 2010 with DSL Rings® technology, I was interested to hear that Bell Labs announced that they had broken the copper gigabit barrier and delivered 10 Gb/s over 30 metres and 1 Gb/s over 70 metres. 

 

Being able to get these speeds out of copper is truly a great accomplishment. The ‘copper revolution’ is making strides and there are a number of proven technologies available to Telcos both now and planned for the future. The technology of choice will depend on:

Economics
The shorter the distance the more fibre is required and hence the weaker the economic argument for using it.  XG.fast is only viable over very short distances (30 – 70 metres) this would appear to negate the financial benefit of using copper in the first place since fibre is required to be deployed very close to the premise.  There may be some cost savings but these would be minimal compared to mBond™, DSL Rings® and VDSL2 Vectoring.

Bandwidth required
Whether 30 Mb/s, 150 Mb/s, or 400 Mb/s is enough, or whether only 1000 Mb/s will do, will obviously impact the choice of technology.

Location and type of premise
G.fast and XG.fast would be best suited to premises in city locations where fibre deployment is most economically viable. Genesis’s mBond technology, designed to backhaul mobile base stations, can also serve business parks and multi dwelling units, whereas Genesis’s DSL Rings technology is for the home broadband user and backhauling small cells over the same infrastructure at the same time. Genesis' technology stands out in the more common distances available in a telecom network over which it can deliver fast broadband over copper making it suitable for suburban, peri-urban and rural locations unsuited to G.fast and XG.fast.

Power availability
G.fast and XG.fast have a power requirement and, given that fibre cannot carry electrical power, the distribution point has to be powered by the premises they serve. This means that the consumer is providing power to the network on their electric utility bill. Service delivery would also be challenged, mainly in the vectoring sense, if a customer unplugs their modem when not in use and especially when they turn it back on.

Deployment model
VDSL2, G.fast and XG.fast create significant cross talk and vectoring is required if maximum bandwidths are to be achieved over distances of 1km or less. A requirement for vectoring presents a deployment challenge because all premises connected to the infrastructure that is going to provide the G.fast/XG.fast-based services, has to be on those services - independent of the cost of those services, etc. In other words, no local loop unbundling, no POTS-only, no choice. It really is all or nothing. This is completely different to DSL Rings which has been designed to work with a flexible deploy as you grow model. The chart below illustrates the positioning of the technologies when considering deployment cost and distance.

It’s great to see an increasing number of copper technologies as vendors and operators realise the economic benefits of evolving copper to meet the broadband needs of tomorrow.

Stephen Cooke, President  & CTO, Genesis Technical Systems