NEC has thrown its hat into the femtocell ring, with an indoor base station, and has proposed a femto technology standard to the Femto Forum.

Femtocells, devices that give 3G coverage indoors and connect to the cellular network over broadband, are expected to appear in consumer trials this year. NEC is offering a network gateway, as well as a choice of femtocells, based on the two major architectures - SIP and UMA - and is jointly proposing its UMA flavor as a standard at the Femto Forum and the 3GPP standards body.

Operators are still furtively testing 3G femtocells in-house, but consumer trials are expected later this year, and ABI Research has predicted that Europe will have the largest femto market, at 16.6 million units a year by 2012, out of a total world market of 36 million units (worth £2.1 billion).

In this secretive climate, at least two major femto architectures have evolved: those which use the SIP standard to connect to the IMS core of the 3G network, and those where the femto mimics a standard 3G base station, using the 3G RAN standard, whose Iu protocol must be carried by another protocol across the Internet.

NEC, along with UMA vendor Kineto, is proposing the UMA protocol to carry the Iu protocol, in a possible RAN femto standard. Originally designed for dual-mode Wi-Fi handsets such as BT's Fusion, and Orange's Unik, UMA is getting a new lease of life as a femto protocol.

NEC is building both kinds of femto, but is promoting the Iu/UMA flavor as a standard, according to UMA software vendor Kineto, NEC's partner RAN femto partner. "Within the femto community, there are two approaches that are really gaining traction, SIP and the RAN gateway," says Steve Shaw, vice president of marketing at Kineto.

Both kinds of femto need standards to succeed, and the Femto Forum has announced a plan to develop agreements among femto manufacturers, so that a limited number of proposals - ideally two - are put before the standards body, 3GPP, to minimize the potential for confusion and deliberate sabotage within the formal group.

"It's important to put our wood behind a couple of arrows," said Shaw. Within the RAN gateway group, he said, "Nokia-Siemens, Huawei, Alcatel and others all use IU over IP, but all have a proprietary way of doing it. We have the top minds of the femto industry coming to Femto Forum meetings. They can streamline the standards for a body like the 3GPP. We want to bring cohesion to what's out there in marketplace."

Kineto and NEC are suggesting UMA the RAN femto standard, because it is already a 3GPP standard, widely implemented in products, said Shaw. "The UMA controller is functionally equivalent to an IU gateway. Ninety percent of the work is already done." The companies have already proposed this approach to the 3GPP and will offer it to the Femto Forum in March, he said.

"What is going to drive this is time to market," said Shaw. "There are literally millions of ports of UMA deployed already. It's vetted, and it's proven."

If UMA wins the vote to become the standard for the RAN gateway type of femtocell, it will then compete with SIP-based femtos, which Shaw says may be too complex. "The SIP-based femto has to take every message and translate it into a SIP message," he said. "That's a chunk of work." RAN gateways avoid this because they appear to the handset like a normal base station.

"The company which can deliver customers with the communications services they require and will pay for is the one which will remain visible and relevant," said Yoichi Watanabe, assistant senior vice president at NEC. "As an established provider of mobile infrastructure expertise, NEC recognized that femtocell-based solutions will provide the best platforms for operators who are planning to offer true FMC services to subscribers."