PMP 450 Planning Guide
Figure 28 One unsynchronized AP 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
transmit cycles of all APs that operate in the same frequency band.
An AP 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 will result from the generated sync. In any other type of link, sync should
be derived from GPS timing.
Advantage of GPS synchronization
Although the embedded timing generation capability of the AP 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 AP of a cluster.
So, the individual AP can synchronize communications between itself and registered SMs, but cannot synchronize
itself with other modules, except by GPS timing (shown in
Figure 29 GPS timing throughout the network
Time
Time
pmp-0047 (March 2014)
1-117
Summary of Contents for PMP 450
Page 1: ...Cambium PMP 450 Planning Guide System Release 13 1 ...
Page 13: ...PMP 450 Planning Guide pmp 0047 March 2014 1 3 ...
Page 42: ...PMP 450 Planning Guide Figure 14 Custom Frequency tab of the SM 1 32 pmp 0047 March 2014 ...
Page 58: ...PMP 450 Planning Guide Figure 16 AP web based management screenshot 1 48 pmp 0047 March 2014 ...
Page 82: ...PMP 450 Planning Guide 1 72 pmp 0047 March 2014 ...
Page 155: ...PMP 450 Planning Guide pmp 0047 March 2014 1 145 ...
