Mobile radio terminal and communication processing method

A mobile radio terminal comprising:

• a circuit switching network transmission/reception unit configured to perform transmission and reception to and from a base station belonging to a circuit switching network including at least one of a UTRAN, a GERAN, and a cdma2000 1x CS access network, with use of a radio signal;
• a mobile communication network transmission/reception unit configured to perform transmission and reception to and from a base station belonging to an E-UTRAN, with use of the radio signal, the E-UTRAN being connected to the circuit switching network and forming an integrated communication network together with the circuit switching network;
• and
• a control unit configured to activate the circuit switching network transmission/reception unit and control the circuit switching network transmission/reception unit so as to maintain synchronization with a base station belonging to the circuit switching network, if the mobile radio terminal is on standby in a base station belonging to the E-UTRAN.

A communication processing method comprising the steps of:

• preparing a mobile radio terminal having a circuit switching network transmission/reception unit;
• performing transmission and reception to and from a base station belonging to a circuit switching network, with use of a radio signal;
• performing transmission and reception to and from a base station belonging to a mobile communication network, with use of the radio signal, the mobile communication network being connected to the circuit switching network and forming an integrated communication network together with the circuit switching network;
• and
• activating the circuit switching network transmission/reception unit and controlling the circuit switching network transmission/reception unit so as to maintain synchronization with a base station belonging to the circuit switching network, if the mobile radio terminal is on standby in a base station belonging to the mobile communication network.