SoftBank Mobile has selected Ericsson's voice over LTE (VoLTE)solution. The network upgrade will support High Definition (HD) voice and video calling, and new enriched multimedia services.
Specifically, Ericsson is upgrading SoftBank Mobile's existing mobile core network (Ericsson Mobile Softswitch Solution and Evolved Packet Core) with a complete IMS core, which includes the Multimedia Telephony Application Server (MTAS). SoftBank Mobile's best-in-class Ericsson-based LTE network is also being upgraded with new VoLTE software. Financial terms were not disclosed.
Ericsson noted that until nationwide LTE coverage is deployed, seamless handover of ongoing voice calls from LTE to WCDMA is needed to ensure uninterrupted voice services as the user moves out of LTE coverage. Ericsson will also deploy this end-to-end network handover functionality, SRVCC (Single Radio Voice Call Continuity).