| 摘要 |
PROBLEM TO BE SOLVED: To surely switch a call channel of a mobile radio station being called by performing voltage-frequency conversion and detecting a moving direction of a mobile radio station by fluctuation of frequency. SOLUTION: When a mobile radio station 1 is calling a place where a command is given as moving along a call zone of a radio base station 4, voltage- frequency conversion signals from control parts 3c to 5c are outputted to a central device 7 at the mobile radio station 1 is moving from the base station 4 toward a base station 3, the signals are compared with each other at a channel connection control part 12 and the mobile radio station 1 is judged to be moving from the base station 4 toward the base station 3 by the fluctuation of the frequency. In this case, since frequency of the voltage-frequency conversion signal from the base station 5 is higher than the frequency of the conversion signal from the base station 4, the moving direction is different from that is judged, when the call is transmitted by a mobile radio station 2 in the call zone of the base station 5 before the call channel is switched from the base station 4 to the base station 3, the call channel is not switched and connected to the base station 5, it is switched to the base station 3 and surely connected to the place where the command is given. |
