MOBILE COMMUNICATION SYSTEM AND COMMUNICATION LINE SWITCHING METHOD IN THE MOBILE COMMUNICATION SYSTEM

摘要

A mobile communication system and communication line switching method in the mobile communication system capable of selecting the communication line, if there is a communication line with a better condition than the current communication line. If there is a communication-possible range with a better condition than a communication-possible range of a communication carrier that currently provides a communication line to mobile telephone 102, a communication carrier that provides a communication line to the communication-possible range is selected to enable communication under management of this communication carrier. By this means, it is possible to select a carrier or service area with a better condition than the currently used carrier or service area in terms of usage rate or service and achieve improvement of user convenience.