| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication system, a mobile station, and a communication method, that are capable of suppressing an increase of IP-CAN processing load caused by a mobile station trying to re-connect to the IP-CAN via a radio access network which does not support services of IP Multimedia core network Subsystem (IMS).SOLUTION: A UE 100 can connect to an Internet-Protocol-compliant IP-CAN via either of LTE which supports services of an IP multimedia subsystem or 3G which does not support services of the IP multimedia subsystem. After a transition from LTE to 3G, when the UE 100 receives a connection rejection notice from a SGSN capable of communicating with the IP multimedia subsystem, the notice indicating that the SGSN cannot connect to the IP multimedia subsystem, the UE 100 stops transmitting an IP access network re-connection request only when the UE 100 exists in the 3G area where the connection rejection notice has been received. |
