| 摘要 |
PROBLEM TO BE SOLVED: To reduce the occupied time of a transmission line and a radio transmission line and the signal processing load of a central station, which are used for measuring a delay time for adjusting the transmission timing of a radio signal. SOLUTION: The central station 1 delays a delay measuring instruction signal S1m by a delay time Di and sends it to the line transmission line 4i and a specified radio base station 2i. At the time of receiving the delay measuring instruction signal S1m addressed to itself from the line transmission line 4i, the radio base station 2i sends back a signal S1r to the central station 1 through the line transmission line 4i in return. The central station 1 receives the returned signal S1r to measure a signal transmission time Ti from the sending of the delay measuring instruction signal S1m to the reception of the returned signal S1r. The central station 1 is capable of simultaneously measuring this signal transmission time Ti concerning all the radio base stations S2. In order to synchronize the transmission timings of the radio signals S2 transmitted by the radio base stations 2 to each other, the central station 1 sets or updates the delay time Di based on the measured signal transmission time Ti. |
