PMP 400/430 and PTP 200/230 Series Configuration and User Guide
pmp-0042 (March 2014)
Page 56 of 98
Table 17: PMP 400/430 AP Control Slot Settings
Number of SMs that
Register to the AP
Suggested Number of
Control Slots
1 to 10
1
1
or 2
11 to 50
4
51 to 150
6
151 to 200
8
Note 1: Any OFDM sector with the
Hi Priority Channel
enabled on any SM
should be configured with at least 1
Control Slot
on the AP.
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
Frame Calculations
and Configuration Settings
on page
48
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. If they are the not needed for data in a given frame the data slot
can be used by the SMs for bandwidth requests. This allows SMs in sectors with zero control slots
configured to still make bandwidth requests using 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
Frame Calculations and Configuration
Settings
on page
48
.
The BHM performs its own ranging and so no range need be set for it.
BHMs do not have settings for control slots, as there is no bandwidth request contention on the one-to-one
link.
DFS and Regulatory Parameters for 5.8 & 5.4 GHz
Radios
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
On the AP/BHM, the “Home => DFS Status” page shows current DFS status of all three frequencies and a
DFS log of past DFS events. Unlike standard Canopy, the PMP 400/430 and PTP 200/230 Series AP, SM,
and BH do not offer “Whitening”, as the OFDM technology obviates the need for it.