| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect a zone where a portable terminal exists. SOLUTION: A calling control circuit 21 automatically and successively calls to a portable terminal 3 from each base station 1A, 1B,... every a fixed time, each station 1A, 1B,... confirms a response from the terminal 3, also measures the intensity of a receiving signal and sends the existence of response and the signal intensity to the circuit 21. They are stored in a storage circuit 7, and the portable terminal is decided to exist in the zone where a base station whose receiving intensity is the strongest among base stations that can connect to the portable terminal exists. |
