Japan’s leading mobile operator by subscribers, NTT DOCOMO, has announced the upcoming launch of its voice-over-LTE (VoLTE) international roaming service in South Korea, on October 7, making it the first Japanese operator to offer a VoLTE outbound roaming service. The cellco says that no fewer than nine of the new smartphones it has unveiled as part of its winter/spring line-up are compatible with the new service, which it claims will enable users to make high-quality voice and video calls. The launch in South Korea comes by dint of a partnership agreement with Seoul-based KT Corporation, one of the country’s largest mobile operators.
VoLTE is proving popular in Japan; mobile users in the country had placed VoLTE calls from more than ten million smartphones as of 31 August, according to DOCOMO research. Its new roaming service incorporates S8 home routed (S8HR) architecture, which is used to enhance the existing LTE data roaming architecture to support VoLTE under a roaming environment. The S8HR architecture is a method based on 3GPP standards to realise VoLTE roaming. Going forward, DOCOMO expects to expand its VoLTE roaming service into other countries through partnerships with local companies.