SWRU423A July 2015 – May 2016 WL1801MOD , WL1805MOD , WL1807MOD , WL1831MOD , WL1835MOD , WL1837MOD
On detection, the AP must notify all connected stations and move to a different frequency. This is done using channel switch announcement elements (IE#37) in beacon frames, probe response frames, and channel switch announcement frames, until the intended channel switch time. This capability is known as dynamic frequency selection or DFS master. DFS master capabilities allow a device to properly utilize the 5-GHz band in an AP role. A Wi-Fi device without DFS master capabilities is permitted to operate as an AP, but only in a small subset of the 5-GHz band, and in certain countries it is limited to indoor applications only.
Radar detection must be done in two scenarios:
After radar detection on a certain channel (during CAC or in-service monitoring), the channel is disabled for any transmission for a predefined period of time. This period is referred to as the non-occupancy period (usually 30 minutes). The device keeps a list of disabled channels and enables each channel when its individual non-occupancy period has expired.