As seen in the Previous article — <Radar Signals and it’s signatures>, The different radar signals have a repetition rate.
The number of successful detection is based on the 802.11 PHY layer detecting the signal (such as a pulse/chirp/frequency-hopping radar signal) and providing the input to the upper layer driver (via a phy error – radar signal detection/an interrupt for radar signal detection).
The Upper layer driver will maintain separate counters and increment the count of such received radar signals. If the count maps to the repetition interval of a particular Radar signal, then the Access Point driver will send the quiet element and also transmit the channel switch element in the beacon or via an action frame.
All WLAN stations need to complete their transmissions within a stipulated time and move away from the channel.