Femtocells could one day proliferate in metropolitan areas at bus stops, on lamp posts, or on buildings, if Vodafone Group plc (NYSE: VOD)’s vision for a hotspot deployment of femto access points becomes reality.

The giant mobile operator's head of new technologies and innovation, Kenny Graham, proposed taking the mini home base stations out of the home/office and onto the streets at the Femtocells Europe 2008 conference in London Wednesday morning.

Graham (a.k.a. the Vodafone Visionary) reckons the same attributes that make femtocells ideal for deployment in homes and offices -– localized coverage, improved performance, self-configuration, self-optimization, and low cost -– can be of use outside, too. He dubbed this kind of deployment a “metrozone.”

”Longer term, you can… get a contiguous network of access points,” he said. “If you create this layer of access points, you will deliver a step change in performance.

”We’ve talked about mesh, software-defined radio, self-organized networks, and base stations on lamp posts for years,” he reminded his audience. “All these technologies were concepts some time ago. The metro access point [femtocell] could be [what] brings these things together to improve performance for the outdoor environment.”

But while this all sounds intriguing, Graham admitted the idea faces a lot of challenges. One of the biggest issues with a metro femto deployment is backhaul. How would an operator backhaul traffic from all those little base stations?

As to the timing of when such an outdoor femto deployment might be practical, he said it could be three years from now, or even longer: The "metrozone" concept seems more appropriate for the so-called 4G technology, Long-Term Evolution (LTE), he added.

For now, though, Vodafone is testing femtocells for the home environment.

”Today, the focus is on the home,” said Graham. “We have to get that working right first. Then, we can start looking to the future and set a path for access points in the future.”

Vodafone is trialing femtocells in Spain with equipment from Huawei Technologies Co. Ltd. and Alcatel-Lucent (NYSE: ALU). Alcatel-Lucent uses femtocell technology and access points from Sagem Télécommunications SA and provides the system integration through a joint development partnership. (See Vodafone, O2 Test Femtocells, Vodafone CEO Seeks Cheap Femtos, AlcaLu Goes Femto, and Alcatel Buys Into 2Wire.)

Graham stressed that the trial in Spain is focused on testing femtocells in the home environment and not the public access point scenario.

Unstrung has also reported that ip.access Ltd. , along with AlcaLu, were the joint winners of a group-wide Vodafone femtocell RFP. But Graham would not comment on whether the trial vendor choices in Spain are indicative of a supplier change at group level for the operator’s femtocell program. (Vodafone Eyes Femto Service This Year, Vodafone CEO Seeks Cheap Femtos, Vodafone Picks Femto Vendors, and Vodafone RFP Fuels Femtocells.)

— Michelle Donegan, European Editor, Unstrung