voice over LTE (VoLTE)

What is voice over LTE?

Voice over LTE, or VoLTE, is a digital packet technology that uses 4G LTE networks to route voice traffic and transmit data. This voice service is the standard for high-speed wireless communications in devices such as smartphones, data terminals, IoT devices and wearables.

VoLTE is important for network operators, vendors, original equipment manufacturers and consumers. Since LTE is a data-only networking technology, VoLTE provides higher quality calls, better service, and the ability to use voice and data simultaneously.

How does VoLTE work?

VoLTE is based on the IP Multimedia Subsystem framework. This enables the service to deliver multimedia as data flows using a common IP interface that can use but doesn't depend on a legacy circuit-switched voice network.

For example, a user might initiate a call using the LTE network. If they wander outside an LTE coverage area, the call will go back to the legacy network. This functionality is known as Single Radio Voice Call Continuity, where the LTE network simultaneously maintains two connections until the LTE signal disconnects.

Additionally, the recommended speech codec for VoLTE is adaptive multi-rate wideband, or HD voice. HD voice increases the audio frequency range for voice calls and raises sound quality.

Support for VoLTE

Most 4G wireless networks use LTE technology and thus support VoLTE. According to a January 2023 report from Global Mobile Suppliers Association, 292 network operators worldwide have invested in VoLTE technology, and 258 of them have launched VoLTE networks.

Most cellular devices have VoLTE capabilities, including any iPhone after the iPhone 6, all Google Pixel models and Samsung Galaxy models after 2015. Users typically have the option to toggle VoLTE on and off through the device settings. To make a VoLTE call, both devices involved in the communication must be compatible with VoLTE, be located in a supported area and have VoLTE capabilities enabled.

Benefits of VoLTE

VoLTE can provide service providers and device users with multiple benefits:

  • Uses spectrum more efficiently than traditional voice technology.
  • Increases battery life when compared to VoIP.
  • Provides a superior audio quality and a clear calling experience.
  • Offers reliable services and interoperability.
  • Lets users make calls and use data simultaneously.
  • Enables up to six-way conference calls.
  • Deploys alongside multimedia services, such as video sharing and multimedia messaging.
  • Simplifies network management and developer accessibility.
  • Frees up network bandwidth due to a smaller packet.

Editor's note: This article was republished in March 2023 to improve the reader experience.

This was last updated in March 2023

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