A wireless device, for operation within a wireless network, the wireless device comprising: a RF transmitter, a RF receiver, and processing circuitry, where the RF transmitter sends a radar-detected message or a channel-switch announcement message to other wireless devices in the wireless networks. The other wireless devices receive the radar-detected message and abandon radar-detected channels designated in the radar-detected message. The other wireless devices also receive the channel-switch announcement message and switch to radar-free channels designated in the channel-switching message.