UMA - Unlicensed Mobile Access

Unlicensed Mobile Access (UMA), also known as Generic Access Network (GAN), was a technology standard that allowed a mobile device to seamlessly switch between local area networks (like Wi-Fi or Bluetooth) and mobile networks (like GSM or UMTS). This offered the advantage of allowing voice, data and other mobile services to be delivered over unlicensed wireless networks, improving coverage and capacity, particularly in areas where cellular signals are weak or non-existent.

In 2006, UMA supplier Kineto Wireless and wireless LAN infrastructure manufacturer Extricom completed interoperability testing between Kineto's UMA solution and Extricom's enterprise wireless LAN infrastructure, demonstrating how mobile operators cpi;d extend their UMA service offerings into the enterprise and commercial hot-zone markets. The testing validated seamless handover and continuity of active UMA voice calls and data sessions between Wi-Fi access points in an enterprise wireless LAN environment. Seamless mobility across access points enables in-office coverage, single-number convenience. UMA-based sessions could transparently move between access point radios, without any interruption in service. All the while, Wi-Fi level security was maintained as well as the IPSec tunnel used to secure UMA services, shifting architecture from a cell-planning to a channel-blanket topology. The technology eliminated the co-channel interference of traditional WLAN systems.

How UMA Worked

1. Device Connectivity: A UMA-enabled device first connects to a local area network, such as Wi-Fi. This could be in your home, at a coffee shop, or any other place with Wi-Fi.
2. UMA Network Controller (UNC): The device then connects to the UMA Network Controller (UNC), which is part of the mobile operator's core network but can be accessed over the internet. The UNC acts as a bridge between the local area network and the mobile network.
3. Authentication and Encryption: Like any mobile connection, the device must authenticate with the network, and the data traffic is encrypted to ensure security. These procedures are the same as they would be on the mobile network.
4. Voice and Data Services: Once connected, the device can access voice and data services just like it would on the mobile network. This includes voice calls, SMS, MMS, and data traffic.
5. Handover: One of the key features of UMA is seamless handover between networks. If you're on a call and move out of Wi-Fi range, the call can be handed over to the mobile network without dropping. Conversely, if you move into Wi-Fi range, the call can be handed over to the Wi-Fi network.

UMA technology allowed mobile operators to extend their service coverage and capacity without the need for expensive investments in additional cell towers. For users, it offered improved service in areas with poor cellular reception, and could potentially reduce costs by offloading mobile traffic to Wi-Fi networks. However, UMA required specific support from both the mobile device and the network operator, and with the rise of other technologies such as Voice over Wi-Fi (VoWiFi) and Voice over LTE (VoLTE), it's less commonly used today.