NEC, Kineto make UMA’s case for femtocells

Some vendors are proposing an IP-Multimedia-Subsystem (IMS) and session-initiation-protocol (SIP) solution that would eliminate the need for a network gateway and make the femtocell a direct extension of the IP network. But since IMS has waned in popularity and actual IMS architectures are still rare, most vendors have fallen into the radio access network gateway approach, which uses the standard IuB interfaces of the macro cellular network. The problem, Shaw said, is that vendors don’t agree on the means of linking that gateway to the femtocell.

“It comes down to which solution can bring femtocells to market as quickly as possible,” Shaw said. “Right now, the NSN version of version of IuB is different from the Ericsson version of IuB, which is different from the Huawei version of IuB,” Shaw said.

While the lack of a unified standard won’t prevent femtocells from going to market, it will prevent them from shipping in high volumes, Shaw said. Most vendors are taking a proprietary approach to the interface, inextricably linking their gateways to their own femtocells. For femtocells to become mass-market products, they have to function like mobile phones, Shaw said—any vendor’s femtocell has to work on any carrier’s network.

Nokia Siemens Networks seems to be the exception among the big vendors. Instead of developing the femtocells themselves, NSN is building the gateways, partnering with femtocell makers to ensure their gear is interoperable. NSN’s interoperability work seems to be done internally among its partners rather than in the standards bodies though, Shaw said.

“Our question for Nokia Siemens is if there is something you think is better with what you’re doing than with UMA, let us know—we’ll add it to UMA,” Shaw said. “But why delay the market for all of these years while you sort it out?”