* Integrated mobile services are just part of the bigger picture
In recent months, I’ve frequently discussed the notion of merging different kinds of wireless services into a consistent, aggregate “mobile experience.” From the subscriber perspective, such unification would allow users to roam among different kinds of networks while seeing no service disruption of a phone call or data session; in effect, extending coverage.
Integrated mobile services might also allow automatic selection of the “best” network connection, be it the one with the strongest signal or the least expensive route.
These are fledgling efforts for now. In the end, they are part of the bigger picture of “fixed mobile convergence,” or FMC, which is the ultimate attempt to turn all landline and mobile Internet access connections into one huge, interoperable, Web services-based environment.
There are a couple primary approaches to mobile convergence with transparent handoff. One is Unlicensed Mobile Access (UMA), known more recently as both Generic Access Network (GAN) and GSM EDGE Radio Access Network (GERAN).
The other, more broadly encompassing, is the IP Multimedia Subsystem (IMS) and its potential successor, “Advance to IMS,” or A-IMS, which brings some enhancements to the table. MobileIGNITE interoperability is the IMS subsystem that specifically deals with wireless handoff component for voice call continuity. (Confused yet?)
There are signs of UMA-based commercial services already. UMA entails providing access to a GSM-based cellular network, which uses licensed spectrum, via an unlicensed wireless network such as an 802.11-based WLAN or an 802.15 Bluetooth network. The setup basically involves the carrier installing a UMA Network Controller (UNC) at the border between the access network and the core network to authenticate and authorize users. The UNC is a counterpart to the Base Station Controller in the cellular network.
Once the user is approved, all mobile voice and data get routed to the user’s dual-mode handset via the unlicensed network until he or she roams back out of 802.11/Bluetooth coverage and into licensed cellular territory.
A commercial consumer service in the U.K. from BT, called BT Fusion, uses the UMA/GAN/GERAN technology. BT Fusion operates like a traditional mobile phone but automatically switches to U.K. landline calling rates when subscribers call U.K. landline numbers from home. Until early this year, the BT service used Bluetooth as the unlicensed access network; with the availability of the Motorola A910 Wi-Fi/GSM handset, however, users now have WLAN access.
And, as mentioned last week, T-Mobile is rumored to have a UMA-based residential Wi-Fi/GSM service in beta trials in the U.S.
Next time: IMS and its derivatives.
