On 4th Nov. 2009, the One Voice initiative was published by 12 companies including AT&T, Orange, Telefonica, TeliaSonera, Verizon, Vodafone, Alcatel-Lucent, Ericsson, Nokia Siemens Networks, Nokia, Samsung and Sony Ericsson. These all agreed that the IMS based solution, as defined by 3GPP, is the most applicable approach to meet their consumers expectations for service quality, reliability and availability when moving from existing CS based voice services to IP based LTE services.
On 15th Feb 2010, GSMA announced that it has adopted the work of the One Voice initiative to drive the global mobile industry towards a standard way of delivering voice and messaging services for LTE. The GSMA’s VoLTE initiative was supported by more than 40 organisations from across the mobile ecosystem, including many of the world’s leading mobile communication service providers, handset manufacturers and equipment vendors, all of whom support the principle of a single, IMS-based voice solution for next-generation mobile broadband networks. This announcement was also supported by 3GPP, Next Generation Mobile Networks alliance (NGMN) and the International Multimedia Teleconferencing Consortium (IMTC).
As per GSA: 71 operators are investing in VoLTE studies, trials or deployments, including 11 that have commercially launched HD voice service. The number of HD voice launches enabled by VoLTE is forecast to reach 19 by end-2014 and then double in 2015. In July 2014 GSA confirmed 92 smartphones (including carrier and frequency variants) support VoLTE, including products by Asus, Huawei, LG, Pantech, Samsung and Sony Mobile. The newly-announced Apple iPhone 6 & 6 Plus models support VoLTE.
Things are also moving quickly with many operators who have announced VoLTE launches and are getting more confident day by day. Du, Dubai recently announced Nokia as VoLTE partner. KDDI, Japan is launching au VoLTE in December. Telstra, Australia has already been doing trials and plans to launch VoLTE network in 2015. Finally, Verizon and AT&T will have interoperable VoLTE calls in 2015.
Below is my summary from the LTE Voice Summit 2014. Let me know if you like it.