When radar/radio signals are detected by one of two access points establishing communication in a WDS mode, the one access point notifies the other access point of a change of a communication channel to a newly allocated channel and actually changes the communication channel to the newly allocated channel. The other access point notified of the newly allocated channel performs a passive scan at the notified newly allocated channel to detect a beacon broadcasted by the one access point. In response to detection of the beacon, the other access point resets the communication channel to the notified newly allocated channel. The two access points can accordingly reestablish communication in the WDS mode within a short time period. This arrangement allows for a quick channel change in response to detection of radar/radio signals, such as a weather radar, during communication of a 5 GHz frequency band in the WDS mode.