Patent attributes
A first radio relay device (21) transmits a first radio frame in which a first pulse has been set, a second radio relay device (22) sends back a second radio frame in which a second pulse has been set according to detection of the first pulse from the received first radio frame, the first radio relay device (21) detects the second pulse from the received second radio frame, and either one of the relay devices adjusts a correction value included in the time synchronization packet using a transmission delay time between the two radio relay devices calculated based on at least the setting of the first pulse and the detection of the second pulse.