USER EQUIPMENT, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

PROBLEM TO BE SOLVED: To enable efficient transition of a communication network in packet communication and to improve a response to a user in the packet communication. SOLUTION: User equipment communicatable in first and second communication networks includes a determiner for determining whether or not transition to the second communication network is necessary upon packet transmission, and a communication controller for transmitting a radio connection request having a transition unnecessary flag set therein to the first communication network when transition to the second communication network is unnecessary. The determiner may determine the necessity or non-necessity of transition to the second communication network on the basis of at least one of an application type, a data quantity, and the transition unnecessary flag set for incoming notification. COPYRIGHT: (C)2011,JPO&INPIT