User's Manual

Table Of Contents
PMP 450 Operations Guide
Using the OFDM Frame Calculator Tool for
Collocation (AP or SM)
pmp-0049 (September 2012)
5-15
Max Range
Downlink Data percentage
(reserved) Control Slots
If OFDM (PMP 430, PMP 450, PTP 230) and FSK (PMP 1x0) APs of the same frequency band are in
proximity, or if you want APs set to different parameters (differing in their Max Range values, for
example), then you should use the Frame Calculator to identify compatible settings.
The frame calculator is available on the Frame Calculator tab of the Tools web page. To use the Frame
Calculator, type into the calculator various configurable parameter values for each proximal AP, and
then record the resulting AP Receive Start value. Next vary the Downlink Data percentage in each
calculation and iterate until the calculated AP Receive Start for all collocated APs are within 300 bit
times; if possible, within 150 bit times.
The calculator does not use values in the module or populate its parameters. It is merely a convenience
application that runs on a module. For this reason, you can use any FSK module (AP, SM, BHM,
BHS) to perform FSK frame calculations for setting the parameters on an FSK AP and any OFDM
module (AP, SM, BHM, BHS) to perform OFDM frame calculations for setting the parameters on an
OFDM AP.
IMPORTANT!
APs that have slightly mismatched transmit-to-receive ratios and low levels of data
traffic may see little effect on throughput. A system that was not tuned for collocation
may work fine at low traffic levels, but encounter problems at higher traffic levels. The
conservative practice is to tune for collocation before traffic ultimately increases. This
prevents problems that occur as sectors are built.