MOBILE COMMUNICATION SYSTEM, NETWORK DEVICE, AND MOBILE COMMUNICATION METHOD

摘要

When the priority of a second communication call that needs to be set is a top priority during a transition process from a first communication system to a second communication system, the second communication system does not set a bearer of a first communication call between the second communication system and a mobile communication terminal, and informs the first communication system that the first communication call cannot be set but that the second communication call can be set. When the first communication system is informed that the first communication call cannot be set but that the second communication call can be set, the first communication system stops a handover process, and issues an instruction to the mobile communication terminal to switch to the second communication system using other processes.