Voice over LTE

Voice over Long-Term Evolution (Volte) is a standard for high-speed wireless communication for mobile phones and data terminals. It is based on the IP Multimedia Subsystem (IMS) network, with specific profiles for control and media planes of voice service on LTE defined by GSMA in PRD IR.92. This approach results in the voice service (control and media planes) being delivered as data flows within the LTE data bearer. This means that there is no dependency on (or ultimately, requirement for) the legacy circuit-switched voice network to be maintained. VoLTE has up to three times more voice and data capacity than 3G UMTS and up to six times more than 2G GSM. Furthermore, it frees up bandwidth because VoLTE’s packets headers are smaller than those of unoptimized VoIP/LTE.8

In May 2014, Singtel introduced the world's first commercial "full-featured" VoLTE service in Singapore, only in combination with the Galaxy Note 3, it was subsequently expanded to the other.

In June 2014, KT showcased the world’s first cross-border roaming services based on Voice over LTE. The South Korean operator partnered with China Mobile to develop VoLTE roaming services.

In October 2014, operators based on IMS local breakout architecture with home routing systems.

In November 2014, Verizon and AT&T announced the companies are enabling VoLTE-to-VoLTE connections between their respective customers. VoLTE interoperability between Verizon and AT&T customers began in 2015. Testing and design are being done between both companies using third party networks such as Alcatel-Lucent.

On 11 July 2015, SEATEL Cambodia announced the world's first commercial 100% VoLTE service without 2G/3G in Cambodia.

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