Specifications
Chapter 4 - Operation Menus and Parameters
BreezeNET B 102 System Manual
looking for another radar-free frequency. The subset of viable frequencies is
configurable.
4.2.6.2.3.2.1 DFS implementation on the BU
The BU maintains a continuously updated database of all applicable frequencies,
where each frequency is marked as Radar Free, Radar Detected or Adjacent to
Radar. The BU attempts to check a new frequency only if it is marked as Radar
Free. If there is no radar activity detected, the units may use this frequency to
communicate. If a radar activity was detected on a certain frequency, it will be
marked in the database as a Radar Detected frequency. The frequency will remain
tagged as Radar Detected for a predefined period of time called Channel Avoidance
Period. After this period expires, the frequency will be marked as Radar Free.
If radar activity was detected on a certain frequency, adjacent channels should
not be used as well, according to the bandwidth. For instance, if the bandwidth is
20 MHz, then if radar activity was detected in 5800 MHz, frequencies 5790 MHz
and 5810 MHz should not be used as well. These frequencies are marked in the
database as Adjacent to Radar, and will be treated the same as Radar Detected
frequencies.
4.2.6.2.3.2.2 DFS implementation on the RB
When DFS is enabled on the RB, the unit uses a channel availability check
mechanism that is similar to the BU’s. Before associating to the BU, the RB picks
a Radar Free frequency and:
If the frequency was previously scanned and tagged as available, it
immediately associates to the BU.
If the frequency, is currently tagged as Radar Free as a result of a Radar
Detected status that expired, or in some cases if the Radar Free validation has
expired (see the note above), the RB will initiate its own channel availability
check. As a result:
» If no radar signal is detected, the RB associates to the BU
» If the RB detects a radar, it will tag the frequency in its own database as
Radar Detected, notify the BU and attempt to connect on another channel
NOTE
Some country codes require a periodical revalidation of the Radar Free frequencies. So additionally,
it might be required for the channel validation period not to have expired as well.