Femtocells To Replace Parts Of The 3G Network

Grown-up versions of femtocells, devices which beef up 3G network strength in the home, are set to take over parts of the outdoor cellular networks, according to technology vendor picoChip.

Femtocells – such as Vodafone’s Sure Signal device – are cut-down versions of mobile phone base stations, redesigned to operate inside buildings, using home broadband networks to route 3G data onto the Internet. Now, picoChip, which claims to provide 70 percent of the chips used to make femtocells, has unveiled a toughened up version, which takes the femtocell idea back out onto the streets.

Multiple users, with chattering smartphones

While home femtocells are gathering momentum – picoChip expects to ship a million femto chips this year – the way is now clear for a larger version, which could go some way to solving the looming capacity crisis on 3G networks, picoChip says.

While demand for data is booming, the amount of data capacity available per user is falling, as the existing bandwidth is shared between more data devices, thanks to the growth of smartphopnes, said Andy Gothard, director of marketing at picoChip. On a graph, the two lines cross over this year, meaning more bandwidth is needed: “The crossover period is now.”

Home femtocells have been designed to handle “smartphone chatter” well, filtering out the wasteful communications that applications like Exchange, Facebook and Twitter continuously send. Despite the value of radio links, he said:

“Instant messaging and Exchange are the worst offenders,” claiming that a smartphone with “always on” applications like Exchange – while doing very little – can produce the same signalling load on the network as a device making 1000 voice calls per day.

Public access femtocells

The 3GPP standards group created a standard for “public access” femtocells, which are in public spaces instead of indoors. picoChip’s new PC333 chip is designed to meet all parts of that specification, including the ability to reach around 2km, and handle mobile devices moving in cars or trains at speeds up to 120km/hour, with a soft handover to the rest of the network. While domestic femtocells only handle around four users, public acccess devices have 32 or 64 channels, said Gothard.

The net result is the production of femtocells which are miniaturised versions of 3G base stations, but with better data capability, packaged as small weatherproof boxes that can be mounted on lamp-posts.

Domestic femtocells took some time to get established – and they are still very much a minority sport – as operators had to market them to end users, something which turned out to be quite tricky.

Public access femtocells, by contrast, will just be part of the operators’ network, invisible except for the performance improvement, so they should roll out much more easily, said Gothard. “Operators are biting our hands off,” he said, especially given the impact on operators’ data costs. “It costs £9 to move 1Gbyte of data via macrocells, and it costs £2 to move it via femtocells.”

He expects trial deployments of the beefy femtocells in the next twelve months, with full roll-out later – and those operators who have worked with domestic femtocells will move fastest, because the technical experience involved will give them a headstart.

At the same time as producing bigger femtocells, picoChip is pushing down the cost of the domestic version, with a reference board, the PC3700, finally getting the materital cost for a femtocell below $50 and the power needs below 5W, making it easy to deploy. “This can be powered over Ethernet or USB,” said Gothard.

picoChip in India

Earlier this year it was announced that PicoChip had been selected by India’s Rancore Technologies to help develop base stations for use in 4G mobile broadband networks in India and around the world. The company has also teamed up with Entuple Technologies to bring advanced 3G and 4G femtocell technologies to Indian industry and academia.

“The pool of talent and expertise in wireless technology development within India is astonishing,” said picoChip chief executive Nigel Toon, speaking at the launch of Enabling Innovation India. “The expertise, talent and collaborative spirit of the Entuple team is a formidable asset in driving picoChip’s ambitions and plans for the Indian market.”