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VoLGA Voice over Long Term Evolution via Generic Access Network

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Voice over Long Term Evolution via Generic Access Network (VoLGA) is a technology that enables the delivery of voice services over Long Term Evolution (LTE) networks using the Generic Access Network (GAN) or Unlicensed Mobile Access (UMA) architecture. It was developed as an interim solution to enable voice services over LTE networks before Voice over LTE (VoLTE) became widely available.

Background:

LTE is a high-speed wireless communication standard that provides data-centric services, such as internet browsing and video streaming, with enhanced performance compared to previous cellular technologies. However, when LTE was initially deployed, it did not support traditional circuit-switched voice calls natively. Instead, voice calls were carried over legacy 2G and 3G networks, causing inefficiencies and complexities for network operators.

The Need for VoLGA:

To overcome the limitation of voice support in early LTE deployments, VoLGA was proposed as an interim solution. It allowed voice services to be delivered over the LTE network using the existing GAN/UMA architecture, which was originally designed for enabling voice over Wi-Fi and unlicensed radio access networks.

How VoLGA Works:

  1. GAN/UMA Architecture: The GAN or UMA architecture enables mobile devices to seamlessly handover voice and data services between cellular networks and unlicensed networks, such as Wi-Fi. It provides a tunneling mechanism to transport voice and data traffic between the mobile device and the core network of the mobile operator.
  2. Tunneling Protocol: VoLGA uses the GAN/UMA tunneling protocol to encapsulate voice calls and transport them between the mobile device and the LTE core network. The voice calls are then converted back to circuit-switched format in the core network before being routed to the recipient.
  3. Handling Handovers: When a VoLGA-enabled device moves between LTE coverage and non-LTE coverage (e.g., from LTE to 2G/3G), the voice call can be seamlessly handed over between the different access networks. This handover is transparent to the user, ensuring continuity of voice calls.
  4. Coexistence with Data Services: VoLGA allows voice and data services to be delivered concurrently over LTE. While data services use the native LTE data bearers, VoLGA takes care of voice calls.

Challenges and Limitations:

VoLGA was designed as an interim solution, and it had some challenges and limitations:

  1. Complexity: VoLGA introduced additional complexity to the network architecture, as it required the coexistence of LTE and GAN/UMA technologies.
  2. Spectrum Efficiency: VoLGA did not make optimal use of the available spectrum for voice calls over LTE, as it still relied on circuit-switched technology for voice transport.
  3. Transition to VoLTE: With the availability and maturation of VoLTE, VoLGA became less relevant as an interim solution, and network operators shifted their focus to deploying VoLTE for native voice support over LTE.

Conclusion:

Voice over Long Term Evolution via Generic Access Network (VoLGA) was a technology developed as an interim solution to enable voice services over LTE networks using the existing GAN/UMA architecture. It allowed mobile devices to deliver voice calls over LTE by tunneling the voice traffic between the mobile device and the LTE core network. However, as Voice over LTE (VoLTE) became widely available and matured, VoLGA lost its relevance, and operators transitioned to VoLTE for native voice support over LTE networks.