1. Field of the Invention
The present invention relates to a mobile communication system and, particularly, to a mobile communication terminal and a communication method therefor which enable two-way communication with a base station.
2. Description of the Prior Art
In general, mobile terminals carried by users are battery-powered. Therefore, it is desirable that their power consumption be minimized. There has been proposed a radio telephone terminal that is intended for such reduction in power consumption in Japanese Patent Application Laid-Open No. 7-303077. This radio telephone terminal is equipped with a detector for detecting the remaining amount of battery power. If the battery remaining power is greater than or equal to a predetermined amount, location registration is performed every time the telephone terminal moves to an adjacent communicable area (cell). If the battery remaining power is smaller than the predetermined amount, the user is merely informed of non-effectiveness of location registration. Further, the time interval of reception of control signals from a base station and that of location registration are varied in accordance with the battery remaining power, to reduce the battery consumption and in turn elongate the usable time.
However, a transmission operation for location registration requires a large amount of power because of driving of a high-frequency amplifier. In the conventional radio communication terminal as described above, because it is necessary to perform, on a regular basis, transmission and reception operations for location registration with the base station, the battery is consumed at a high rate and the usable time cannot be made sufficiently long.