Kamalini Ganguly, Analyst, Ovum
UK: Alcatel-Lucent has created a 300Mbps pipe using what it has dubbed “Phantom Mode” technology to create a “phantom” channel in between two physical copper pairs, applying vectoring to eliminate the resultant cross-talk and bonding all three pairs, real and virtual.
As Alcatel-Lucent itself points out, creating a phantom channel is not new; a version of a phantom mode circuit was invented in 1886. DSL bonding and vectoring are technology advances being adopted by other vendors too (Ericsson, for example). But what Alcatel-Lucent has demonstrated is the impact of combining all three elements.
The technology can be extended to multiple pairs, creating multiple phantom channels that would boost existing bandwidth capacity between 50% and 100%, but the most realistic scenario remains the consideration of two copper pairs, which is present in much of the US and Europe. Given the potential bandwidth boost possible, the additional cost of using this technology would be low because it would use existing copper lines.
Challenges will take time to resolve
Alcatel-Lucent is working on the development of a compatible DSL modem that will support three bonded pairs and on the integration of this technology into its DSL line cards. Additional challenges will be to eliminate potential electro-magnetic interference issues while improving energy efficiency.
Alcatel-Lucent will market this technology as part of a standardized solution. Vectoring will be a part of the VDSL2 standard only, so using this technology over ADSL (still the dominant DSL technology worldwide) would take it outside the standards domain, and the bandwidth boost would be much smaller.
For VDSL, the benefits would be maximum at or around the 400-meter range, beyond which point the VDSL bit rate declines significantly. This means that, in order to achieve the promised 300Mbps, providers may still have to roll out FTTN, FTTC, or even FTTB if not already deployed. (At greater distances, the speed will be lower but can still be competitive.)
It’s another arrow in the arsenal of a service provider that is facing competition and intends to roll out FTTH eventually, but only has the time and resources to roll it out to the curb for the time being.
Will it be too late for Alcatel-Lucent and other vendors pursuing DSL technology advances?
The timeline for the benefits of these DSL developments to reach the market remains a challenge. Bonding trials were held by Alcatel-Lucent in November 2009 and vectoring field trials are scheduled later this year.
We may see commercial deployments of these two technologies in the next couple of years but utilization of both along with the Phantom Mode is still some years away. Meanwhile, AT&T is scheduled to finish its FTTN+VDSL U-verse deployment to 30 million US households by 2011.
For service providers in Europe that state regulatory uncertainty as a barrier to deploying next-generation access networks, these technology breakthroughs will present attractive alternatives. Also, despite the FTTH gains around the world, the reality is that service providers still struggle to provide fiber access, especially the last few hundred meters to the home, which often accounts for a significant proportion of deployment costs.
VDSL will defy the DSL slowdown given its role in reaching the customer in FTTB, FTTC, and FTTN deployments. Alcatel-Lucent, with a leading 54 percent share of the VDSL market globally, stands to benefit from the success of any technologies or techniques that extend the life of the DSL market, particularly VDSL.