Table 3: Control Slot Settings - Motorola 5440AP - Canopy 5.4 GHz AP User Manual Supplement

Canopy 400 Series OFDM AP and SM
if the Downlink Data % is set to greater than 85% and the user enters a range greater
•
than 5 miles, the module will reset the Downlink Data % to 85%
if the range is set to greater than 5 miles and the user enters a Downlink Data % of
•
greater than 85%, the module will reset the Downlink Data % to 85%.
Suggested Control Slot settings as a function of number of SMs in the sector are shown in Table
3. Generally all APs in a cluster should use the same number of control slots so as to keep the
frame structures, and thereby the send and receive timing, the same.
In some cases, operators may find that sectors with high levels of small packet requests, such as
might be seen in a sector handling several VoIP streams, benefit overall from slightly higher
Control Slot settings. If different sectors require different numbers of Control Slots, the operator
should use the Frame Calculator to find a combination of settings that put "Rec SEQ Start" times
within 300 bit times. See section 3.5.2 on page 14 for details.
Control Slots are reserved for SMs' bandwidth requests and never handle data. A higher number
of control slots gives higher probability that an SM's bandwidth request will be heard when the
system is heavily loaded, but with the tradeoff that sector capacity is reduced by about 100 kbps
for each Control Slot configured, so there will be less capacity to handle the request.
Uplink Data Slots are used first for data, but if not needed for data in a given frame can be used
by the SMs for bandwidth requests. So, even with zero control slots configured, the SMs can still
make bandwidth requests, using any unused data slots.
Downlink Data %, Range, and Control Slots should be set consistent with the results of any
collocation planning done using OFDM and FSK frame calculators in section 3.5.2 on page 14.
4.4 DFS AND REGULATORY PARAMETERS
Dynamic Frequency Selection (DFS) is a requirement in several countries and regions for 5 GHz
unlicensed systems to detect radar systems and avoid co-channel operation. DFS and other
regulatory requirements drive the settings for the following parameters, as discussed in this
section:
Region Code
•
Primary Frequency
•
Alternate 1 and Alternate 2 Frequencies
•
External Antenna Gain
•
Release 8.4 has a new page, "Home => DFS Status", that shows current DFS status of all three
frequencies and a DFS log of past DFS events. Note, unlike standard Canopy, the Canopy 400
Series AP and SM do not offer "Whitening", as the OFDM technology obviates the need for it.
Version 1, April 2008

Table 3: Control Slot Settings

Number of SMs that Number of Control
Register to the AP Slots Recommended
1 to 10
11 to 50
51 to 150
151 to 200
0
1
2
3
User Guide
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