UMA is a radio access technology that enables IPsec tunneling of GSM traffic over a fixed-line network via an 802.11 WLAN access point. As such, it is already a fixed-mobile convergence offering in that it enables a specially prepared dual-mode handset to use GSM networks when out and about, and a WLAN connection when in the subscriber’s homezone.
The current level of technology makes it a residential/SoHo offering, however. Malcolm Latham, marketing manager for seamless mobility at Motorola Networks in EMEA, said: Standard WLAN implementations don’t support micro-mobility, i.e. handover between APs, which is not an issue in the residential market, where single APs are the norm, but it would be for enterprise.
The only UMA service commercially available today is the Fusion offering from the UK incumbent BT Group Plc, and even that is a pre-standard implementation using Bluetooth rather than WLAN for the in-home wireless connectivity. Schaumberg, Illinois-based Motorola is the technology provider for that service and has another seven carriers trialling UMA around the GSM world, primarily in Europe.
One of the shortcomings of the Fusion service as it stands today, apart from the more limited scope of Bluetooth compared to WLAN, is that although the subscriber enjoys fixed-line charges when calling over a WLAN network at home, people phoning in continue to pay for calls to a mobile phone. Latham said the technology Motorola is developing for inclusion in its UMA portfolio will overcome that issue.
The first thing the operators will be able to do is allocate a fixed-line number to the handset, which will only work when you’re in the homezone, going to voicemail when you’re not, or be forwarded to the mobile number if you set up call forwarding, he said. That will still require the subscriber to maintain two numbers, but at least will overcome the issue of only being reachable on a mobile one.
Beyond that, Motorola is carrying out closer integration between the fixed and mobile networks, enabling functions such as dual ringing, whereby more than one handset will ring at the same time so that the call can be answered from any one of them, and sequential ringing, in which phones will ring in a predetermined sequence as the call is forwarded from one to another. It will all be configurable over the web, said Latham.
