PTP 450 Configuration and User Guide
Configuration options for TDD synchronization
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pmp-0815 (August 2015)
Is not synchronized with any of the other BHMs.
Is transmitting nearby the other BHMs while they are expecting to receive BHS
transmissions from a maximum distance.
Figure 44
One unsynchronized BHM in cluster resulting in self-interference
The result is self-interference. In this scenario, the self-interference can be avoided only by
synchronizing the TDD transmits cycles of all BHMs that operate in the same frequency
band.
A BHM that is isolated by at least 5 miles (8 km) from any other equipment can generate
and pass sync pulse without GPS timing and not risk that interference results from the
generated sync. In any other type of link, sync must be derived from GPS timing.
Advantage of GPS synchronization
Although the embedded timing generation capability of the BHM keeps a precise clock
(configuration parameter Sync Input set to
Generate Sync Signal
), no trigger exists to
start the clock at the same moment in each BHM of a cluster. So, the individual BHM can
synchronize communications between itself and registered BHSs, but cannot synchronize
itself with other modules, except by GPS timing (shown in
