A dual-type wireless communication terminal has been known as a wireless communication terminal capable of performing communication by switching between two communication systems.
Patent Document 1: JP-A-H9-172675
Of the above dual-type wireless communication terminals, a wireless communication terminal, which can measure a wireless communication status of one communication method during communication using another communication method and monitor an incoming call, is especially called a hybrid type.
In relation to the hybrid-type wireless communication terminal, a hybrid-type wireless communication terminal using a cdma2000 1× system which is mainly designed for voice communication and a 1×EVDO system which is specifically designed for data communication suspends the data communication of the 1×EVDO system at predetermined intervals (e.g., 5.12 seconds) and then switches an antenna and a radio section to the cdma2000 1× to perform system monitoring with the cdma2000 1×, in order to monitor an incoming call of the cdma2000 1× during the data communication with the 1×EVDO. When the system monitoring has been completed, the antenna and the radio section are again switched to the 1×EVDO, thereby resuming the data communication with the 1×EVDO. In the case that the wireless communication terminal is located in an area where is in the vicinity of a boundary between service areas by a plurality of base stations as cdma2000 1× system (the case that quantities of signals received from the plurality of base stations (C/I values) contend with each other), the cdma2000 1×, thereby performing the system monitoring with the cdma2000 1×. At this time, when the idle handoff of the cdma2000 1× system has been detected and the idle handoff is continuously detected even after the idle handoff processing, the antenna and the radio section of the wireless communication terminal are still occupied with the cdma2000 1× system. Therefore, after a given period of time has elapsed while the occupation is maintained, the wireless communication terminal as the 1×EVDO system determines that radio wave is lost (see FIG. 4). For this reason, during data communication of the 1×EVDO, the data communication of the 1×EVDO system is disconnected as a result of repetition of the idle handoff in the cdma2000 1× system, although the state of radio wave of the 1×EVDO system is good.