The name UMA (not the actress but unlicensed mobile access) might seem to suggest some renegade networking platform that can bypass the legacy regulatory stronghold on wireless spectrum, but names can be a bit misleading.
UMA does allow users to access mobile services interpreted here as GSM network services over a variety of 'unlicensed' mobile technologies, including Bluetooth, wireless LAN, and yes, WiMAX. The system doesn't exactly extend to the GSM access network, but instead extends GSM and GPRS signaling onto an IP platform such as the Internet.
By accessing the Internet, users can then access standard GSM services. The system has been refined to support not only all GSM services when accessed using UMA, but also to support seamless handoff between GSM and UMA networks.
And the technology has an incredible amount of backing behind it, including Nokia, Motorola, Sony Ericsson, and a number of big European and American operators.
At the moment, the technology has been deployed primarily for so called home-zone services that let users make calls on their mobile phones at designated areas, such as in the home, and pay cheaper fixed-line prices. So despite its reference to 'unlicensed,' suggesting that it might be 'free' in some way, UMA is far from it.
In fact, what UMA does is to allow mobile operators to extend the mobile business model into the IP world, meaning they can now charge for calls even if they are made over the Internet, over a Wi-Fi connection. The value proposition for users is that the calls can be made from mobile phones with seamless handover.
For now, there are lots of limitations for UMA. The user must be able to log onto the UMA network seamlessly for handover to work, and in most cases the operator will have to control the UMA hotspot in order to offer this kind of service.
The true potential of UMA probably won't arrive until the widespread rollout of something like WiMAX, which can cover large areas. With UMA, cellular operators can theoretically supplement their cellular coverage with cheaper WiMAX gear.
Seen from the other side, UMA can represent a way for wireless hotspot operators to set up their own cellular service, a true form of 'unlicensed' mobile service. By setting up a GSM core network, hotspots can now be turned into any other cell site, offering the full range of GSM services. UMA is certainly an intriguing development, especially given the fact that 3G SIMs are finding their way into laptop computers that are also equipped with Wi-Fi.