Written by: Martin Bäckström, Andreas Havdrup, Tomas Nylander, Jari Vikberg and Peter Öhman

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What do you get when you combine mobile telephony with voice over IP (VoIP)? Mobile@Home. The solution is a new access network for mobile core networks that has the same role in the mobile network as GSM/EDGE and WCDMA radio access networks (GERAN/UTRAN) but makes use of unlicensed spectrum and IP-based broadband access networks. It is based on the 3GPP Generic Access Network (GAN) specification (formerly known as Unlicensed Mobile Access, UMA).

WithMobile@Home, end users can use their GSM terminals at home to access mobile services over wireless LAN (WiFi or Bluetooth). The solution minimizes operator investment by reusing the existing mobile core network and other support nodes.

Background
In 2000, Ericsson began investigating how unlicensed radio in a mobile handset could be used to access mobile network services. Not long afterward it developed a demo system to show that every major GSM service can indeed be supported over Bluetooth radio and an IP-access network.

In late 2003, Ericsson helped establish the Unlicensed Mobile Access (UMA) forum for this idea. The forum labored for nine months to produce a set of specifications that supported every major GSM service over unlicensed radio. The specifications were released in September 2004.
Just before the release of the first specification, UMA was included as a work item in the Third Generation Partnership Project (3GPP) under the name Generic Access to A and Gb Interface (GAAG). Within 3GPP, the UMA technology specification is called Generic Access Network or GAN.
The GAN specifications have since been approved for inclusion in 3GPP Release 6
(Rel-6). All future work related to unlicensed mobile access will take place in 3GPP and will be coordinated with standardization and development of the GSM and UMTS networks