February 26, 2015

DOCOMO Successfully Verifies VoLTE Roaming in Commercial Environment
— Trials included first full end-to-end QoS and first transoceanic VoLTE roaming call —

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R&D

TOKYO, JAPAN, February 26, 2015 --- NTT DOCOMO, INC., a personalized mobile solutions provider for smarter living, announced today that together with KT Corporation of South Korea and Verizon Wireless of the United States it has successfully verified the feasibility of international voice-over-LTE (VoLTE) roaming between different regions of the world.

The trials used S8 Home Routed (S8HR) architecture, a technology based on the existing LTE data roaming platform, which allows speedy commercialization of VoLTE for high-definition voice and video roaming services with full end-to-end carrier-grade voice and video quality. As a result of the successful efforts, DOCOMO is now preparing to offer its customers the same VoLTE experiences they have in Japan when traveling to other countries.

In the trials, DOCOMO and KT achieved the world's first high-definition voice and video call with full end-to-end quality of service. Also, DOCOMO and Verizon achieved the world's first transoceanic high-definition VoLTE roaming calls. DOCOMO has existing commercial 3G and 4G roaming relations with Verizon Wireless and KT.

The calls were made on an IP eXchange (IPX) and network equipment to replicate commercial networks. With only two months of preparation, which also proved the technology's feasibility of speedy commercialization, the quality of VoLTE roaming calls using S8HR architecture over both short and long distances was proven to be better than that of existing 3G voice roaming services.

DOCOMO will continue to collaborate with these and other companies in the GSMA to drive the industry's ongoing discussion of international VoLTE roaming architecture, and to develop related operational guidelines aiming at the accelerated global deployment as part of the GSMA's Network 2020 Programme. DOCOMO will continue to carry out related R&D as it prepares to commercialize international VoLTE roaming services by the end of 2015.

(Open a PDF file)(Appendix) Overview of the Trials (PDF format: 89KB)

About NTT DOCOMO

NTT DOCOMO provides innovative, convenient and secure mobile services that enable smarter living for each customer. The company serves over 65 million mobile customers in Japan via advanced wireless networks, including a nationwide 3G network and one of the world's first commercial LTE networks. Leveraging its unique capabilities as a mobile operator, DOCOMO is a leading developer of cutting-edge technologies for NFC mobile payments, mobile GPS, mobile TV, intuitive mobile assistance, environmental monitoring, smart grids and much more. Overseas, the company provides technical and operational expertise to eight mobile operators and other partner companies. NTT DOCOMO is listed on the Tokyo (9437) and New York (DCM) stock exchanges. Please visit https://www.nttdocomo.co.jp/english/ for more information.

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