100 Mbps DSL is Here & 800 Mbps is Around the Corner

nodecalevectoring

It is mind boggling to think that copper, thanks to new generation DSL technologies is staying competitive with fiber and cable broadband. Today, a new breakthrough shows that it will only be a matter of time before DSL broadband crosses the 800 Mbps threshold. And while we wait for that massive speed bump, we are beginning to see the commercial availability of DSL that can deliver 100 Mbps.

These recent upgrades in the DSL speeds are coming at a handy time – DSL has started to lose market momentum, and carriers are looking for ways to balance their exploding capital expenditure requirements. While fiber networks are better in the long run, most phone companies need to squeeze out more from their copper networks without losing too much ground to cable broadband rivals. Why? Because they have to shift their capital expenditure dollars to beefing up wireless networks, which themselves are growing through an explosive growth.

Ikanos, a maker of broadband chips today introduced a new technology, NodeScale Vectoring, DSL access technology that allows connections at 100 Mbps and higher, something which has not been possible on many of the phone company networks. According to the chipmaker, the cost of deploying this technology is about a tenth of the cost of building a fiber to the home network.

The NodeScale technology allows carriers to eliminate the crosstalk that occurs on copper pairs when offering very high-speed Internet. The cross talk introduces noise in the network, which in turn limits the line quality and thus reduces the performance of the network. Typically, to handle crosstalk issues, one needs gigabytes of memory. There are two ways of handling cross talk. NodeScale essentially tames cross talk at the DSLAM level as opposed to line card vectoring which treats every line card as a separate crosstalk domain.

Ikanos claims its NodeScale Vectoring technology cancels noise efficiently, and ZTE Corporation will demonstrate the first DSLAM employing the technology.  The technology was developed in-house, but Ikanos also licensed the dynamic DSL technology developed by DSL pioneer John Cioffi’s ASSIA.

Back in 2006, Professor Cioffi (of Stanford University) told me that it would be possible to hit Gigabit speeds over DSL. We are inching pretty close to that. We have written about many experiments which have pushed DSL speeds to over 300 Mbps in lab conditions. Huawei, the Chinese telecom equipment maker recently announced that it has tested speeds of up to 700 Mbps.

Today, Nokia Siemens Networks took that even further, announcing that it has tested a technology that could boost the data-carrying capacity of standard copper wires to 825 Mbps over a distance of 400 meters of bonded copper lines and 750 Mbps over a distance of 500 meters. If it is made commercial, it would allow the carriers to eek out more from their copper infrastructure.

NSN does this by the creation of phantom (or virtual) channels that “supplement the two physical wires that are the standard configuration for copper transmission lines.” The approach is called Phantom DSL and can boost bandwidth by between 50 percent to 75 percent over the existing bonded copper lines. NSN hopes to make it part of its DSLAM products. Alcatel-Lucent’s Bell Labs came up with the Phantom DSL technology and announced it back in April 2010.

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