Generic Access Network
Have you heard about Generic Access Network? It is an evolving wireless communications system within which mobile sets operate seamlessly between local area networks (LANs) and wide-area networks (WANs). Using GAN technology; a mobile phone subscriber will communicate by speech; data and multimedia through large-scale cellular and small-scale Wi-Fi systems. Usually, all handoffs between systems occur without disturbing the communications session.
As GAN technology is implemented, cellular phone subscribers will expect improved coverage. The ability to use one phone set for all their voice communications. And maybe cheaper rates with a single bill for net and voice communications.
However, phone set technology for GAN use involves two different modes, each of that should be constantly accessible. This needs that each phone set have two transceivers active at all times. One for typical cellular service and the other for Wi-Fi. This provides an increased current demand on the battery.
The core function of GAN technology may be a dual-mode handset service that permits mobile subscribers to seamlessly hand over connections between wireless LANs and WANs. This increased feature of seamless roaming permits users to connect with people everywhere the globe at a lower price using handset devices.
Along with its benefits, GAN has some limitations. As UMA uses different frequencies, GAN subscriber services are often prone to interference. Mobile devices that use multiple signals of both LAN and WAN via GAN are comparatively expensive. And reduce the mobile device’s talk and standby time.
One of the important applications of GAN/UMA is the Dual-mode Handset service. Now let us see how this works:
With dual-mode services such as Wi-Fi and GSM, subscribers make calls from outside the house as they’d normally, using the GSM radio network at the quality tariff rate. However within the house, the call travels over the subscriber’s wireless broadband connection. Therefore the operator will enjoy an identical economic structure as VoIP-over-broadband provider.
GAN/UMA isn’t the primary system to permit the utilization of unauthorized spectrum to connect handsets to a GSM network. The GIP/IWP standard for DECT gives similar functionality. But needs a lot of direct connection to the GSM network from the base station. Whereas dual-mode DECT/GSM phones have appeared, these have typically been functionally cordless phones with a GSM phone built-in, instead of phones implementing DECT/GIP, Because of the shortage of appropriate infrastructure to hook DECT base-stations supporting GIP to GSM networks on an ad-hoc basis.
The local network is also based on private unauthorized spectrum technologies like Bluetooth or 802.11; whereas the wide network is alternatively GSM/GPRS or UMTS mobile services. Using the cellular network, the mobile handset communicates over the air with a base station, via a base station controller, to servers within the core network of the carrier.
Under the GAN system, once the telephone detects a LAN. It provides a secure IP connection through a entry to a server referred to as a GAN Controller (GANC) on the carrier’s network. The GANC translates the signals returning from the telephone to create it seem to be returning from another base station. Thus, once a mobile moves from a GSM to an 802.11 network, it seems to the core network as if it’s just on a distinct base station.1