Seoul, South Korea – On April 10, 2015, LG Uplus, one of the leading mobile operators for LTE technology, announced the world’s first commercial launch of VoLTE roaming services featuring HD voice by leveraging the LTE data roaming from LG Uplus to KDDI in Japan. While many operators worldwide have trialed VoLTE roaming services, this is the world’s first successful commercial launch.

Since August 2012, LG Uplus has offered subscribers Hybrid VoLTE services via multiple LTE networks. Also, LG Uplus launched Single VoLTE services in July 2013 based on LTE-A Carrier Aggregation technology for enhanced bandwidth. LG Uplus now supports the world’s first HD voice and video calls on its partners’ VoLTE networks unlike other roaming operators only supporting voice calls over 3G networks.

Through this successful VoLTE roaming launch,subscribers can enjoy HD voice and video calls offering enhanced quality, nearly real-sound experience, and minimal call connection delay. This quality standard is made possible by enhanced 50-7000 Hz speech bandwidth via AMR-WB (Adaptive Multi-Rate Wideband) codec. VoLTE technology allows subscribers to enjoy call connection speeds 20 times faster than 3G (0.25 sec. faster).

LG Uplus has domestically offered various All-IP based communication services since launching LTE in 2011 such as changing HD voice calls to video calls in real-time and sharing music, location, photos, and other contents during HD voice calls. Successful launching of VoLTE roaming services now allows LG Uplus subscribers to use these services while roaming abroad. Additionally, this will become a great foundation to build momentum toward enhanced, next-generation roaming services.

Since the start of 2014, LG Uplus has collaborated with other leading LTE operators and succeeded with trial testing in November 2014 based on the S8 Home Routed VoLTE roaming architecture. Through several cycles of trial testing and evaluation, both partners have worked to improve the user experience until successfully launching. The S8 Home Routed VoLTE roaming architecture, connection between Visited Network’s SGW (Serving Gateway) and Home Network’s PGW (Packet Gateway) using built-in Home Network IMS, allowed LG Uplus to more efficiently develop VoLTE roaming services without additional architecture changes.

LG Uplus is offering this service initially to LG G-Flex 2 users roaming with KDDI in Japan and will expand with new countries and new devices as released. “This launch is the result of the efforts to allow our roaming subscribers abroad the same enhanced domestic experience” according to an LG Uplus spokesperson. “I expect other worldwide mobile operators will follow in this endeavor to commercialize VoLTE roaming services in the near future.”