| 摘要 |
<p>A relay device (20) is configured to calculate predicted time (TPg) which is back from a fixed point and until a time point at which the relay device starts to prepare for reception of a beacon signal, based on time (Tpa) required to prepare for reception of the beacon signal, synchronization header reception time (TPb), and environment error time (TPy), start to prepare for the reception at time (t1) which is the predicted time back from predicted reception time (t2) of the fixed point, and obtain actual measurement time (TPm) which is from the time at which the relay device starts to prepare for the reception until actual reception time (t3) of the fixed point, compensate its internal clock based on a history of an error (”TP) which is a difference between the predicted time and the actual measurement time, and transmit the beacon signal to the lower device after the relay device has compensated the internal clock, wherein the lower device compensates its internal clock based on the beacon signal transmitted from the relay device (20) after the relay device (20) has compensated the internal clock.</p> |
