| 摘要 |
PROBLEM TO BE SOLVED: To provide a mobile communication system capable of handing over a communication terminal apparatus to a network of packet switching, while a VoIP call using line switching is continued.SOLUTION: An HSS(authentication server) 25 stores an IP address used for a VoIP call using line switching, by a communication terminal apparatus 1. In hand over, an MME (movement management server) 23 makes an inquiry to the HSS 25 about the IP address used by the communication terminal 1, assigns to the communication terminal 1 an IP address equal to the IP address used for the VoIP call using the line switching as the IP address of an LTE network, and hands over the communication terminal apparatus 1 from a 3G network to the LTE network. |
