Femtocells can answer mobile signal woes

FEMTOCELLS ARE ESSENTIALLY a British innovation, according to Nigel Toon, chief executive of Picochip. Simply, they are router-sized boxes that consumers or businesses can use to create miniature indoor base stations that will cover their local area.

Installation involves plugging the femtocell into an existing broadband connection and registering the relevant mobile phone numbers with the operator.

Thereafter, when users are within range of the femtocell they are no longer sharing a public mast but have their own personal cell with a better signal-to-noise ratio. They are particularly important now that so many mobile users are beginning to use data as well as voice.

"Mobile networks have traditionally been designed for voice traffic," Toon says, "and what's starting to happen is that data networks are showing the same pattern as the public switched telephone network in the early 1990s."

On 1 July, Vodafone will become the latest mobile network operator to begin selling femtocells to customers in the UK. In the US AT&T is rolling them out nationally. In Japan, DoCoMo is using them to put wireless coverage around train stations

According to Toon, the concept of femtocells is quite recent. "We showed it in 2003 to 2004. A brand new technology coming to market within five years is actually pretty quick for a new technology," he says.

Especially, he adds, mobile technologies, "because there's lots of regulation and huge amounts of testing" for both emissions and standards conformance.

As data use continues to grow exponentially, the stronger signal and better use of network capacity will become increasingly important. Femtocells also, Toon says, use less electricity and also help the battery inside the mobile phone last longer because they work at low power levels. Phones roam seamlessly from femtocells to the public macro cells.

Some have argued that femtocells are shifting onto consumers and businesses costs of network build-out that should be borne by the mobile network operators themselves. For Toon, however, that's a selling point since the networks are his customers, demand for data is accelerating, and expanding the existing infrastructure is expensive and controversial.

As anyone who's been to a local planning meeting knows, no one wants a full-size mobile phone mast in their back garden, no matter how much they want mobile phone coverage. "For mobile operators it's a big benefit," he says. "They can catch and keep you as a customer or get whole enterprises - it's cheaper and less controversial for them."

Toon has been with Picochip for three years. Before that, he spent 13 years running the European side of chip manufacturer Altera and then, with three friends, became co-founder of the British start-up Icera, which developed some of the first HSPA 3G device chips.

Picochip, so named because the company expected to build very small cells, was founded in 2001 by the company's CTO, Doug Pulley to design technology for wireless infrastructures. It's not a box manufacturer; it makes the chips and software.

The idea of tiny, cost-effective base stations, based on some of Pulley's original ideas about how to build small cells and optimise networks, is a "rapidly emerging major business", Toon says. As part of promoting the concept, Picochip has helped form the industry association Femtoforum to drive standardisation efforts.

"The thing people were really concerned about was, can femtocells be deployed without interfering with the rest of the network? That's now been proved," says Toon. The other most common question, he adds, is how to manage and deploy the cells when the numbers are in the millions.

"Mobile carriers have to find a way to provide enough capacity so it's seamless," he says. "At home, femtocells will get people off the macro network. In offices, serve them off enterprise femtocells, and then other areas where they will start to appear are around towns in public spaces and rural areas, where they're a way for carriers to extend 3G coverage capacity cheaply and effectively. You put up a box and the box works out how best to cover the area."

Femtocells do rely, however, on plugging into an existing fixed line IP network. "But they allow you to distribute many more cells in the network, so you're effectively reusing the spectrum in the network many more times and getting more capacity and more coverage," Toon says.

Toon believes that femtocells will allow consumers to switch to using mobile phones for all voice calls and do away with cordless and DECT phones attached to landlines. In addition, he thinks that as mobile phones become an increasingly significant piece in securing transactions, particularly for credit card authentication, people will really need their mobile network to work at home.

"We are basically reshaping the way mobile networks get built – a new topology," he says. µ