Weidmuller Wireless Ethernet Modem & Device Server WI-MOD-E-G/A User Manual
Rev.
2.16
www.weidmuller.com
38
DTIM Period (AP only)
DTIM sets which beacon frames incorporate extra information for low power
sleeping client devices. Normally set this to 1.
RTS Threshold
“Ready To Send”
RTS frames can be used to help avoid radio collisions between two stations
that cannot directly hear each other. Any frame larger than RTS Threshold
bytes will be preceded by an RTS message. The default value of RTS
Threshold is 2346, which effectively disables RTS signaling, as this value is
larger than the maximum frame size (Fragmentation Threshold).
Fragmentation
Threshold
(Client Stations only). The maximum transmission unit (MTU) of data over the
radio. If more than this number of bytes is input into the module, it will be
transmitted in more than one message (or fragmented).
Interference Mitigation
(AP only)
Interference Mitigation should only be turn on (Default is Off) if using Demo
Whip antenna’s or if there is a high level of background interference.
By enabling this option the radio will dynamically adjust radio parameters to
help mitigate interference based on any background interference. It will reduce
the receiver sensitivity and so should only be enabled on paths with a high
fade Margin and good signal quality, etc.
Bursting
Selecting this option can increase the data throughput by reducing the
overheads associated with wireless transmissions. If communicating with a
device that does not support bursting the modem will drop back to non-
bursting mode.
Enable Iperf Server
Enable Iperf Server function in the modem. Iperf is used for performing Radio
surveys or radio path testing. See section 4.4 - “Throughput Test”
Fixed Noise Floor
Allows the Radio Receiver Noise Floor (and therefore sensitivity) to be moved
above any interference. What this will do is essentially stop the radio
communicating with devices with lower signal strength. For use in areas where
there is a greater amount of interference
Fixed Noise Floor
Due to the popularity of the 2.4 GHz band, there are many sources of interference. This interference can sometimes be a
problem due to the way 802.11 devices communicate. Standard 802.11 communications uses a system called “Clear
Channel Assessment” which means the radio will listen before transmission and if the channel is busy it will hold off
regardless of the level of signal.
If the background interference is high due to other radio systems or noise you can raise the Fixed Noise floor to
compensate. The Channel Utilisation page can be used to identify excess noise / interference.
Raising the Noise Floor will block out any receive signal levels below the value configured under “Fixed Noise Floor “on
the Advanced Radio Configuration page. The value must be entered as a negative dBm number and should be at least
8dB greater than the
weakest
RSSI of any connected modems, otherwise communications may be lost.
E.g. if the interfering noise levels are around -80 dB you can raise the Noise floor to -70dB to block out any signals below
making sure the RSSI levels of any connected modules are not below this Noise Floor as they will not communicate.
The Connectivity page can be used to determine what other systems are around and what their RSSI levels are.
After configuring the fixed noise floor, confirm that the Channel Utilisation has dropped to a desirable level, and where
possible perform an iperf Throughput Test to confirm acceptable performance.
