Posted: 27th Oct, 2010 By: MarkJ

Nokia Siemens Networks (NSN), a recognised telecoms giant, has become the latest to prove that existing
copper phone line infrastructure is far from dead. It has demonstrated a DSL technology that can deliver "
super-fast" broadband download speeds of up to a staggering
825Mbps (Megabits per second) over a distance of 400 metres, or
750Mbps over 500 metres.
The feat bests Chinese firm,
Huawei, which last month used its
SuperMIMO technology and "
four twisted pairs" (i.e. technically four phone lines bonded together) to boost the maximum speed of DSL to 700Mbps (Megabits per second) over 400 meters (
here).
Prior to that
Alcatel-Lucent's research arm, Bell Labs, achieved a broadband DSL download speed of
300Mbps (
here) via
DSL Phantom Mode at identical distances of up to 400 meters (or 100Mbps at 1km). However this method only bonded two telephone lines together (i.e. 150Mbps each).
By contrast Nokia's solution also uses a similar
Phantom DSL method, which creates a virtual (phantom) channel to supplement the
two physical wires that are the standard configuration for many copper transmission lines. In theory this might make it more adaptable to UK networks, although BT already has a big contract with Huawei that might give their tech precedence.
Nokia's Head of its Broadband Access Business Line, Eduard Scheiterer, said:
"Laying down new optical fiber to the home remains costly, though it is capable of delivering very high speeds and is a definite solution for long-term bandwidth requirements. However, the innovative use of technologies such as phantom circuits helps operators provide an efficient last mile connectivity with existing copper wires."
It's certainly quite a leap above BT's current UK best of 40Mbps via
Fibre to the Cabinet (FTTC). FTTC delivers a fast fibre optic cable to BT's street level cabinets, while the remaining connection (between cabinets and homes) is done using VDSL2 (similar to current ADSL broadband but faster over short distances) via existing copper cable. BT FTTC speeds are expected to be boosted to reach 'up to' 60Mbps in the not too distant future.
As a result Nokia claims that its new solution (
hiX 562x/3x DSLAM) promises a bandwidth increase of 50-75% over existing bonded copper lines, which could prolong the life of copper networks and delay the need for full fibre optic rollout's (i.e. protecting the operator’s existing capital investments).
However, as wonderful as all these innovations are, it remains to be seen how they perform in the real world where
Electromagnetic Compatibility (EMC) is a huge problem and some homes exist further from the cabinet than 400 metres. EMC is used to describe how effectively a system is able to function in an electromagnetic environment without introducing EM disturbances that interfere with the operation of other electrical products.
As it stands BT remains unconvinced, but interested, by all these new developments. Despite being quite old, DSL technology is still improving and could yet offer some surprises. Mind you.. nobody ever talks about upload performance in these tests or what happens at distances of greater than 1km.