A group of fourteen other leading service providers, infrastructure suppliers and handset manufacturers in the wireless industry, have published a set of open specifications for extending mobile voice and data services over wireless LANs. Companies that participated in the development of the Unlicensed Mobile Access (UMA) specifications include Alcatel, AT&T Wireless Services Inc., BT PLC, Cingular Wireless LLC, Ericsson AB, Kineto Wireless Inc., Motorola Inc., Nokia, Nortel Networks Inc., O2, Rogers Wireless Inc., Siemens AG, Sony Ericsson, and T-Mobile USA.
With the UMA specifications now available, service providers can look to deploy interoperable solutions that enable subscribers to roam and handover seamlessly between cellular networks and public and private WLANs using dual-mode mobile handsets. With UMA technology, subscribers receive a consistent set of mobile voice and data services as they transition between access networks. Solutions based on the UMA specifications support the handover of active mobile voice calls and data sessions between networks, ensuring no interruption of service.
"There has been no shortage of one-off fixed-mobile products and solutions over the years," said Peter Jarich, senior analyst, wireless infrastructure, Current Analysis. "The release of the UMA specifications is especially important because they point to a critical mass of carrier interest in convergence while finally providing vendors with an open set of specifications to build to."
"As a key participant in their development, we believe the UMA specifications for Cellular/WLAN convergence represent a significant milestone within the wireless industry," said John O'Connell, president and chief executive officer, Kineto Wireless. "To support the broad deployment of UMA-based services, Kineto is providing a number of UMA-compliant products and services for service providers and the mobile device community."
Development of the UMA specifications began in late 2003, with the participating companies sharing a common goal of creating, specifying and promoting a technological solution for extending mobile voice and data services over unlicensed spectrum technologies, including Bluetooth and 802.11. The UMA specifications available though the UMA technology web sites are intended for use by vendors of wireless communications systems and applications to develop UMA compatible solutions.
How UMA Technology Works
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- A mobile subscriber with a UMA-enabled, dual-mode handset moves within range of an unlicensed wireless network to which the handset is allowed to connect.
- Upon connecting, the handset contacts the UMA Network Controller (UNC) over the broadband IP access network to be authenticated and authorized to access GSM voice and GPRS data services via the unlicensed wireless network.
- If approved, the subscriber's current location information stored in the core network is updated, and from that point on all mobile voice and data traffic is routed to the handset via the Unlicensed Mobile Access Network (UMAN) rather than the cellular radio access network (RAN).
- ROAMING: When a UMA-enabled subscriber moves outside the range of an unlicensed wireless network to which they are connected, the UNC and handset facilitate roaming back to the licensed outdoor network. This roaming process is completely transparent to the subscriber.
- HANDOVER:If a subscriber is on an active GSM voice call or GPRS data session when they come within range (or out of range) of an unlicensed wireless network, that voice call or data session can automatically handover between access networks with no discernable service interruption. Handovers are completely transparent to the subscriber.
