Auto Frequency Scan; Scan Threshold Trigger - Redline RDL-3000 Series User Manual

RDL-3000 FAMILY
7.6

Auto Frequency Scan

Phase I - Scan Local Frequency Ranges
Scanning begins with the lowest frequency in the Local Frequency Ranges list. The first
channel is calculated with the formula:
signals are detected, the channel, RSSI, and beam direction (RAS only) are recorded.
Subsequent channels are calculated based on the active channel size (except 0.875
MHz channel step size is 1.0 MHz). Monitoring is performed for all frequency ranges in
the Local Frequency Ranges list.
Notes:
1. The order frequency ranges are entered by the operator is ignored. The frequency
scanning function always begins with the lowest range and proceeds to the highest.
2. If the Local Frequency Ranges list is empty, channels are calculated based on the
radio step size.
3. Each channel frequency is monitored for approximately 0.5 seconds. For example,
the scan time for ten range entries, where each entry is one discrete channel:
10 channels x 0.5 s/channel = 5 s
Phase II - Register with a Discovered Sector Controller
When all channels have been monitored for RF signals, the subscriber attempts to
establish a wireless link with the sector controller with the highest measured signal
strength. Attempts are repeated as required for all channels in the list proceeding from
highest to lowest signal level. If all attempts are unsuccessful, or the list is empty, Phase
I is repeated.
During each attempt, the subscriber must monitor the sector controller signals and wait
for an opportunity join the network. The total negotiation time to achieve 'link up' may be
up to 90 seconds. This total wait time includes initial monitoring of the selected channel
to ensure the subscriber can correctly decode the sector controller signals. Other timing
factors include channel size, encryption, etc.
Phase III - Fallback to Scanning All Channels
If the Local Frequency Ranges list is empty, or Phase I & II has been repeated for 8
hours without registering with a sector controller, the subscriber switches to a full
spectrum frequency scan to monitor all available channels on the radio. At the
completion of each full frequency sweep, registration attempts are performed as
described in Phase II. The full scan repeats indefinitely.
7.7

Scan Threshold Trigger

After the RDL-3000 has established a wireless link, the sector controller monitors the
uplink and downlink burst rates. The Rescan Interval timer is started if either the uplink
or downlink burst rate drops below the minimum burst rate set in the Subscriber Link
Configuration screen. If the burst rate recovers to a level equal or higher than the
threshold before the timer expires, the Rescan Interval timer is stopped and the counter
is reset. Otherwise, if the burst rate remains below the threshold for the full Rescan
Interval time, the RDL-3000 drops the link and starts a new frequency scan.
The following diagram illustrates the timing cycles used for the scan threshold trigger.
Example:
Settings: Rescan Interval is 45 s and minimum UL/DL UBR is 9 Mbps.
1. RDL-3000 is powered-on (startup requires ~45 s).
70-00158-03-00
USER MANUAL
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