| 摘要 |
JNTTD-750-PCT 42 In a mobile communication system capable of switching between a first communication state and a second communication state, in a case of a first communication state, a VoIP media signal is 5 exchanged between a mobile station UE #1 and a mobile station UE #2 via an LTE radio access system and a node S-GW, a VoIP control signal is exchanged via the LTE radio access system, the node S-GW, and IMS, and in a case of a second communication state, a circuit-switched signal is exchanged between the mobile station UE #1 and an enhanced 10 MSC/MGW via a 2G/3G radio access system, the VoIP media signal is exchanged between the enhanced MSC/MGW and the mobile station UE #2 via the node S-GW, and the VoIP control signal is exchanged between the enhanced MSC/MGW and the mobile station UE #2 via the node S-GW and the IMS. |
