Friday, April 20, 2007

UMA-enabled Femtocells?

A common question I get is “when femtocells arrive, won’t they displace UMA?” First off, what is generally meant by this is not ‘...displace UMA’ but more accurately ‘...displace dual-mode handset services.’ UMA, as we all know, is a generic IP access technology that can be used to implement a dual-mode handset (DMH) service with cellular/Wi-Fi phones but it’s not actually tied specifically to Wi-Fi.

However, as a generic IP access technology for mobile services, UMA actually plays a key role in a mass-market femtocell solution.

As the operators begin to plan for a robust deployment with hundreds of thousands of femtocell access points into the network, some stringent requirements have emerged:

- An industry recognized, well defined standard such than any femto AP can be interoperable with any core network controller

- “Internet grade” security to run over the public broadband network

- A high-capacity, scalable controller to support thousands of concurrent connections

- The ability to support “consumer” behaviors of unplugging access points, moving access points, plugging in access points where they don’t belong (different countries)

- A protocol which supports a retail femtocell distribution model such that each AP is “standard” out of the box and can self-configure/attach to the network

- And it goes without saying: cost-effective core network controller solution that will not throw the business case out of whack.

Initially, many suppliers jumped to the conclusion that the existing protocol (known as “Iu-B”) which runs between the radios (or “node-b”) and the controller (or RNC) in a macro UMTS network would be sufficient.

But after digging in a bit, it’s pretty well understood that Iu-b was designed to meet a different set of deployment requirements. Iu-b was architected to support a handful of extremely high capacity radio connected over private, secure, managed links.

This is nearly the exact opposite of a femtocell deployment, with many thousands of low capacity (in terms of concurrent calls) radios, all connected over un-managed and un-secured IP networks.

UMA however, was designed for just such a deployment scenario. UMA offers a well defined, robust protocol with a secure connection to the mobile core. In a DMH deployment, UMA supports hundreds of thousands of devices with relatively low concurrent capacity, quite similar to the femtocell usage model. As a well defined standard, femtocell technology suppliers such as UbiquiSys and others can develop UMA-enabled products which interoperate with UMA controllers from Motorola, Nokia, Ericsson and Alcatel.

As operators begin to leverage the public internet and broadband IP to deliver mobile services, UMA will be used for more applications beyond DHM and femtocells. UMA is truly becoming the ‘Universal’ Mobile Access protocol.

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