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Detects interference from other systems and to avoid co-channel operation with these systems,
notably radar systems.
Provides an aggregate a uniform loading of the spectrum across all devices.
To address the primary aims the Spectrum Management algorithm implements a radar detection
function which looks for impulsive interference on the active channel only. If impulsive
interference is detected Spectrum Management will mark the current active channel as having
detected a radar and initiate a channel hop to an available channel. The previous active channel
will remain in the radar detected state for thirty minutes after the last impulsive interference pulse
was detected. After the thirty minutes have expired the channel will be returned to the available
channel pool.
The radar detection algorithm will always scan the active channel for 60 seconds for radar
interference before using the channel. This compulsory channel scan will mean that there is a 60
seconds service outage every time a radar is detected and that the installation time is extended
by 60 seconds even if there is found to be no radar on the channel.
NOTE On system installation or start-up this extends the initial scan time of the Master unit by 60
seconds.
To address the "provide aggregate uniform loading of the spectrum across all devices"
requirement, the channel selection algorithm will choose a channel at random from a list of
available channels. The channel selection algorithm is initiated at link initialisation and when
radar interference is detected.
5.3.2
RTTT Avoidance And Other Channel Use Restrictions
Where regulatory restrictions apply to certain channels these channels are Barred. The user
should note that the number of channels barred is dependant on the channel raster selected. For
example see the effect of the UK RTTT channel restrictions in Figure 11. Barred channels are
indicated by a "No Entry" symbols displayed on the "Spectrum Management" web page, see
section 8 Web Page Reference .
Band Edge
5725 MHz
5732 MHz
5732 5738 5744 5750 5756 5762 5768 5774 5780 5786 5792 5798 5804 5810 5816 5822 5828 5834 5840
5734 MHz
5734 5740 5746 5752 5758 5764 5770 5776 5782 5788 5794 5800 5806 5812 5818 5824 5830 5836 5842
5736 MHz
5736 5742 5748 5754 5760 5766 5772 5778 5784 5790 5796 5802 5808 5814 5820 5826 5832 5838 5844
Lower Centre
Frequency
5.4
5.4 GHZ SPECIFIC FREQUENCY PLANNING CONSIDERATIONS
To fully utilize the 5.470 to 5.725 GHz of allocated spectrum the operator must adjust the lower
center frequency attribute in the installation wizard, described in detail in 8.3.6 "Install Wizard
Pages" Adjustment of the lower center frequency allows the operator to slide the available
frequency settings up and down the 5.4 GHz band. See Figure 12.
Issue 3.1, July 2006
UK RTTT Restricted Channels (Shaded)
Figure 11: 5.8 GHz UK RTTT Channel Avoidance
Band Edge
5850 MHz
Default
Page 29 of 162
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