Thursday, June 05, 2008

3GPP Selects Femtocell Standard, and it’s not (exactly) UMA/GAN

It was announced by multiple sources this week that 3GPP selected a reference architecture for femtocell-to-core network connectivity. This isn’t the completed standard, but sets the framework for the 3GPP RAN 3 working group to develop a full specification. The plan of record, per the 3GPP, is for the full stage 2 and stage 3 documents to be completed by Dec 2008 (in Release 8).

As has also been point out recently, the existing 3GPP UMA/GAN specification was one of a few architectures being considered as the basis for a formal 3GPP femtocell standard. The net result is that the UMA/GAN standard, as is, was not chosen. Sad but true. In order to reach an industry consensus on a HNB architecture there was a measure of compromise from all the participating companies. That’s the nature of standards: compromise.

However, while the HNB reference architecture is not full UMA/GAN, it adopts a number of key principles first introduced in the 3GPP GAN standard. For example, at the highest level, it follows an access-based (rather than core-based) approach, leveraging the existing Iu-cs/Iu-ps interfaces into the core service network. It also identifies the use of a specific protocol for solving a number of challenges associated with the ad-hoc deployment of devices over the internet.

Frankly, while the UMA community would have been delighted if 3GPP had adopted GAN lock-stock-and barrel (as they say in the US) as the formal femtocell standard, the likelihood has always been low. Fortunately, the agreed femtocell architecture builds on several core principles of GAN, which will help accelerate the market.

ThinkFemtocell has a good breakdown of different elements of the work.

For at least a little while longer, UMA/GAN remains the only 3GPP standard which supports femtocells today...

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