Receiver Start of
Packet Detection Threshold (RX-SOP) determines the Wi-Fi signal level in dBm at
which an AP radio will demodulate and decode a packet. The higher the RX-SOP
level, the less sensitive the radio is and the smaller the receiver cell size
will be. By reducing the cell size, we ensure that the clients are connected to
the nearest access point using the highest possible data rates. This is ideal
for high density environments such as stadiums and large auditoriums where
there are a large number of client devices connected per AP. In a high density
environment, the smaller the cell size, the better.
As the RX-SOP value
increase, only packets of a higher RSSI value are decoded by the AP’s radio.
This decreases the cell size as shown in the figure above, but ensures that all
clients are connected with a good RSSI value.
The following is an
example of an AP receiving 802.11 packets. All frames received with weaker RSSI
than configured RS-SOP will be classified as non-WiFi frames and will not get
decoded by the radio, only packets with acceptable RSSI values are decoded.
Packets that are not decoded are treated as non-WiFi interference and detected
at the AP as noise.
In this example, the
RX-SOP threshold is set to low, so authentication requests sent at -84 dBm are
not decoded, but when the same message is sent at -36 dBm, it is decoded.
Table 1 RX-SOP Template
||Use radio default
||Use radio default
The RX-SOP default
threshold value is
means that the RX-SOP threshold is set to the radio’s default value.
RX-SOP is supported
on the following APs:
3500, 3600, 3700
via the WLC GUI
To configure the
RX-SOP threshold on a global level, go to
>Advanced > Rx Sop Threshold.
value can be selected for the 2.4 GHz and the 5 GHz band. This value will be
set globally for all APs. Only an RF Profile can override these settings.
via a RF Profile
To create a new RF
Profile, from the WLC GUI, go to
Wireless > RF
Profile, and then click
Enter a RF Profile
name and select a band. A separate profile must be applied to the 2.4 GHz band
and 5 GHz band.
tab and choose the desired RX-SOP threshold.
profiles can be modified to include an RX-SOP Threshold. You need not create a
new profile solely for RX-SOP.
The RF Profile
must now be applied to an AP Group. Go to
Advanced > AP Groups, then either add a new group or modify an existing
tab, select the pre-band RF Profiles with the desired RX-SOP
To complete the AP
Group configuration, additional steps such as adding WLANs and selecting APs
are required. These steps are not listed as part of this guide.
via the WLC CLI
config 802.11<a/b> rx-sop threshold <level>
auto Revert 802.11a radio receiver SOP to auto
high Set 802.11a radio receiver SOP to high
low Set 802.11a radio receiver SOP to low
medium Set 802.11a radio receiver SOP to medium