Verizon Wireless completed the first IMS-based VoLTE (Voice over LTE) call over its commercial network on at 9:54 a.m. ET Tuesday, Feb. 8, 2011. 
The initial call was placed by Balaji Raghavachari, manager of technology for Verizon Wireless, using a LG Revolution 4G smartphone from Verizon headquarters in Basking Ridge, N.J. The call was received by Sanyogita Shamsunder, director of technology for Verizon Wireless, who was also on a LG Revolution 4G smartphone in Basking Ridge. The initial call was 33 seconds in duration. The participants were were able to browse the Web and use other data services while participating in voice calls. Subsequent test calls lasted more than 10 minutes.
Verizon Wireless plans to enhance VoLTE with rich communications services and optimize performance on its commercial 4G LTE network during 2011. Commercial services are expected to be available in 2012.
“The GSMA launched a voice over LTE initiative a year ago with the aim of driving a single, industry-wide solution for voice and messaging services via IP,” said Alex Sinclair, chief technology officer at the GSMA. “We commend Verizon Wireless for helping to make this a reality by conducting the world’s first voice call over a commercial LTE network. The progress made by the GSMA, its members, and in particular Verizon Wireless, to enable this functionality will play a crucial role in driving strong momentum and vast economies of scale for LTE all over the world.”http://www.verizonwireless.com/LTE
- In November 2010, at Mobile Asia Congress 2010, ZTE demonstrated IMS-based Voice over LTE (VoLTE) calls running CSL’s LTE network in Hong Kong and its existing mobile networks. The calls finished between IMS clients as well as IMS client and conventional 2G/3G handsets.
- The GSMA’s VoLTE initiative is based on IMS (IP multimedia subsystem), which supports voice call service features such as call waiting, call hold and call barring, and is highly scalable to serve very large subscriber bases. IMS also provides mobile operators with the ability to offer services that can integrate voice calls with enhanced, rich features such as presence, instant messaging and video content, delivered in an interoperable and multi-operator environment. Fall back mechanisms to circuit-switched voice services over existing 2G/3G networks is also being worked on.
