NTT Docomo, Japan’s largest mobile operator, said it plans to launch Voice over LTE (VoLTE) services by the end of June. Four smartphones and two tablets in the firm’s device portfolio, by that time, will become compatible with the new service through a software upgrade.
VoLTE users, said NTT Docomo, will be able to make “high quality” voice calls while still maintaining an LTE data connection.
The operator added that the service will enable users to receive ‘Area Mail’ disaster-information notifications while simultaneously making VoLTE voice/video calls.
The service will require a subscription to Xi (the brand name for NTT Docomo’s LTE service). Existing billing plans to Xi, packet flat-rate services, discounts and dialling charges will be applicable to VoLTE voice calls.
Packet communication charges for VoLTE video calls will be offered free of charge until September 2015, after which video calls will incur both voice and packet communication charges.
VoLTE, an all-IP approach to voice connectivity, holds out the promise to network operators of reducing operational costs, particularly if they can phase out their circuit-switched domains (which NTT Docomo has already done).
Another VoLTE advantage is that it frees up spectrum for mobile broadband and developing other services.
IMS-based VoLTE, backed by the GSMA, has widespread industry support but commercial rollout by major operators beyond South Korea has so far been limited.