Vendors Unite on Femtocell Architecture

The Femto Forum Ltd. says its members have reached a consensus on the way femtocells should interact with mobile core networks, an agreement that should speed up the creation and adoption of femtocell standards. (See Femto Forum Touts Progress.)

Femtocell vendors are meeting this week to hammer out the finer details of the agreed interfaces, with plans to send submissions as early as next week to the 3rd Generation Partnership Project (3GPP) , where there are already three work items in progress related to the tiny home base stations.

Given the aggressive schedule set by the Forum and its members, it's expected that a femtocell standard can be completed in "months."

The resulting standard, once implemented, should, in theory, enable any standards-based femtocell to be integrated into any mobile operator's network and femtocell gateway product, and that will ultimately lead to more product choice for consumers.

By agreeing on the interfaces, the Forum believes it has removed one of the barriers that have discouraged some operators from making the leap from trial to soft commercial launches.

"We've enabled operators to move forward faster on their deployments," says Simon Saunders, chairman of the Femto Forum. "For many operators, until they have a clear path toward standardization, they won’t take that first deployment step. So we’ve set out a roadmap, and now more operators are willing to take that step."

Saunders described the agreement as a "no compromise situation." And the speed at which the femtocell vendors, which only announced their intentions to define a common architecture in January, reached a consensus is impressive, considering there are about 15 different ways to integrate home base stations into mobile core networks. (See Femto Forum Tackles Integration and Cisco, Ericsson Swell Femto Forum Ranks.)

According to Unstrung sources, the Forum's operator members had a big hand in driving through an agreement, which indicates just how committed carriers are to deploying home base stations, and how critical standardization and interoperability are for those deployments. (See Softbank Trials Femtocell, Is AT&T Putting Out Femto Feelers?, Vodafone CEO Seeks Cheap Femtos, FT Preps Femtocell RFP, Sprint Goes Femto, TeliaSonera Preps Femto Trial, Vodafone Eyes Femto Service This Year, Verizon Checks Out Femtos, Vodafone, O2 Test Femtocells, and Ukrainians Fancy Femtocells.)

The Forum has agreed that the interface between the femtocell access point and the femtocell gateway -– which the Forum refers to as the "Fa interface" -- will be a modified Iu interface. Saunders says this week's meetings will help determine which flavor of "femto Iu" will be modified: For example, unlicensed mobile access (UMA) is one flavor of an Iu interface.

The Forum has also adopted a "collapsed" architecture, where the NodeB and radio network controller (RNC) functionality will be placed in the femtocell access point, which will optimize signaling over the broadband connection.

"The femtocell is more like a network in a box... it will have a lot of intelligence in it," says Saunders. "It's what operators have been used to having."

None of vendors use a modified Iu approach right now, which means all the suppliers will have to make changes to their equipment. The time it takes for standards-based commercial products to be available from the completion of a standard is generally about 18 to 24 months.

"If we all have to move a bit, that's OK, it's for the better of the industry," says Andy Tiller, vice president of marketing at ip.access Ltd.

The Forum also announced it has established cooperation agreements with the Broadband Forum , to work on service provisioning issues, and the GSM Association (GSMA) .

The Forum also added 19 new members, including AT&T Inc. (NYSE: T), China Telecom Corp. Ltd. (NYSE: CHA), Nortel Networks Ltd. , SK Telecom (Nasdaq: SKM), Sprint Nextel Corp. (NYSE: S), Telenor ASA (Nasdaq: TELN), T-Mobile International AG , and T-Mobile USA .

— Michelle Donegan, European Editor, Unstrung