The Femto Forum Ltd. announced the addition of more than 30 member companies today, a move that significantly grows its ranks from a handful of startups to include major operators and equipment vendors. (See Industry Forms Femto Forum and Femto Forum Forms.)

Today's announcement shows there is growing momentum behind femtocells, the tiny base stations that improve voice and data coverage in homes and offices. (See Vodafone RFP Fuels Femtocells, FT Preps Femtocell RFP, Is AT&T Putting Out Femto Feelers?, and Sprint Goes Femto.)

That momentum has been fueled by other developments involving some of the mobile industry's biggest names.

For example, Motorola Inc. (NYSE: MOT), one of the Forum's new members, has just announced its first 3G femtocell trial with a European operator. (See Moto Trials 3G Femtocell.)

And just last week Unstrung reported that Vodafone Group plc (NYSE: VOD) has chosen Alcatel-Lucent (NYSE: ALU) and ip.access Ltd. to supply 3G its femtocells. (See Vodafone Picks Femto Vendors.)

While Vodafone isn't among the Forum's new operator members, the names on the list show that carrier interest in femtocells isn't limited to any one region: New members include India's Bharti Airtel Ltd. (Mumbai: BHARTIARTL), Bouygues Telecom from France, Hong Kong's PCCW Mobile HK Ltd., Canada's Rogers Wireless Communications Inc. (NYSE: RCN; Toronto: RCM), and regional powerhouse Telefónica Europe plc (O2) .

Telefónica O2 is understood to have two preferred suppliers for femtocells. The operator has conducted trials with Huawei Technologies Co. Ltd. , and is now testing several suppliers in the U.K. and Spain, according to an industry source.

Interestingly, while much femtocell activity has focused on increasing indoor coverage of 3G data networks, Telefónica O2 is also looking at 2G as well as 3G femtocells. According to our source, the operator is particularly interested in using 2G femtocells to help improve coverage in small public places, such as shops and restaurants. (See 3G & WiMax Femtocells: The Operator View.)

Regarding Motorola's trial with a European operator, the vendor offered scant details. The initial stages include lab tests and friendly user trials of Motorola's standalone femtocell in one market of a pan-European operator. Later on, the operator plans to trial Motorola's integrated femtocell solution. (See Femto Players Gun for Gateways.)

"[The trial] is focused on one particular country initially, which is not to say it won't go to other countries," says Malcolm Latham, Motorola's EMEA solutions marketing manager.

Motorola's standalone femtocell in this trial is understood to be based on Ubiquisys Ltd. 's ZoneGate 3G femtocell, but Latham would not confirm this. "We don't discuss who our suppliers are," he says.

Motorola is just one of Ubiquisys's partners, and the relationship covers not just standalone femtocell development, but also an integrated femtocell that would reside in Motorola's residential gateway products. (See UbiquiSys Gets Google Boost, Femtocell Startup Pockets $25M, ABI Rates UbiquiSys, and Ubiquisys, Softbank Demo .)

Other major equipment vendors that have joined the Femto Forum include Alcatel-Lucent, NEC Corp. (Tokyo: 6701), Nokia Networks , Sagem Télécommunications SA , Thomson S.A. (NYSE: TMS; Euronext Paris: 18453), and ZTE Corp. (Shenzhen: 000063; Hong Kong: 0763). (See AlcaLu Goes Femto, Thomson, IP.access Team, NEC, Ubiquisys Team, NSN, Airvana Team, and NSN Intros 3G Femtocell.)

— Michelle Donegan, European Editor, Unstrung