UMA/GAN is the 3rd Generation Partnership Project (3GPP) global standard for subscriber access to mobile circuit, packet and IMS-based services over any IP-based access network, including the Internet. With GAN, mobile operators can now leverage the cost and performance advantages of IP access technologies (DSL, cable, Wi-Fi...) to deliver high-quality, low-cost mobile voice and data services in the locations where subscribers spend most of their time - the home and office.

GAN provides a standard, scalable, secure IP interface into the core service network of mobile operators. By deploying a GAN Controller (GAN-C), mobile operators can extend all existing and future circuit, packet and IMS-based services over any IP-based access network, including the Internet. The GAN standard, while initially developed to deliver mobile services over Wi-Fi, can be leveraged to deliver a number of compelling new fixed-mobile convergence services.

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Feature Phones:  Initial UMA/GAN deployments focused on dual-mode handsets (DMH) – feature phones with integrated Wi-Fi radios.  These DMHs were deployed aggressively by mobile operators to drive fixed-mobile substitution (FMS) by offering low-cost calling when subscribers were attached to Wi-Fi access points. 

Terminal Adaptors: The market for broadband telephony service has increased dramatically over the last few years. At the end of 2009, Vonage Holdings alone had nearly 2.5 million subscribers paying between $15 and $25 per month for a fixed-line telephone service delivered over existing broadband access connections.

With a GAN-enabled terminal adaptor, mobile operators can also participate in this large and growing service opportunity. A GAN-based fixed-line VoIP service is the ideal approach for mobile operators looking to increase FMS by directly capturing in-home fixed minutes of use.

GAN-enabled terminal adaptors enable mobile operators to leverage their existing mobile core networks to deliver a standard analog telephone service over broadband access networks (a.k.a. broadband telephony). As far as subscribers are concerned, the service behaves as a standard analog fixed telephone line. The service is delivered in a manner similar to other fixed-line VoIP services, where a simple device (in this case the terminal adaptor) is connected to the subscriber's existing broadband service.

Mobile VoIP Client: Connecting laptops to broadband access at hotels and Wi-Fi hotspots has become a standard part of everyday life, particularly for international business travelers. In addition, many travelers utilize laptops and broadband connections for the purpose of voice communications. They are turning to PC-based soft-phones and VoIP services when making international calls, rather than using mobile phones to make calls and pay significant roaming fees. This represents a significant threat and opportunity for mobile operators.

Thanks to GAN, mobile operators are able to leverage their existing GAN deployments to provide their own mobile VoIP service (also known as 'the Skype Killer').  With a GAN-based mobile VoIP client, mobile service providers can extend their existing voice and SMS services to a subscriber’s PC, laptop or netbook. 

Ideally a mobile VoIP client would be bundled with a 3G USB dongle, enabling new mobile data subscribers access to mobile voice services.  When the dongle is plugged into the laptop, the application would start automatically.  It could be linked to the subscriber’s own mobile phone subscription, providing a mirrored service experience, or it could function totally independent of any other subscriptions. 

Alternatively, the mobile VoIP client could be distributed as a stand-alone application, running on non-cellular devices like the Apple iPod or iPad.  In this manner, mobile operators could provide a viable alternative to Skype for a wide range of consumer electronics devices.