Chapter 3: System planning
Link planning
Page 3-24
Calculating Fade Margin
Free space path loss is a major determinant in Rx (received) signal level. Rx signal level, in turn, is
a major factor in the system operating margin (fade margin), which is calculated as follows:
System operating margin (fade margin) dB = Rx signal level dB
−
Rx sensitivity dB
Thus, fade margin is the difference between strength of the received signal and the strength that
the receiver requires for maintaining a reliable link. A higher fade margin is characteristic of a
more reliable link.
Adaptive modulation
Adaptive modulation ensures that the highest throughput that can be achieved instantaneously
will be obtained, taking account of propagation and interference. When the link has been installed,
web pages provide information about the link loss currently measured by the equipment, both
instantaneously and averaged. The averaged value will require maximum seasonal fading to be
added, and then the radio reliability of the link can be computed.
For details of the system throughput, link loss and maximum distance for each frequency band in
all modulation modes, see
Link
on page
10-35
.
Summary of Contents for PMP 450 Series
Page 125: ...Chapter 3 System planning Typical deployment Page 3 3 Figure 37 Wall installation...
Page 126: ...Chapter 3 System planning Typical deployment Page 3 4 Figure 38 Roof installation...
Page 127: ...Chapter 3 System planning Typical deployment Page 3 5 Figure 39 GPS receiver wall installation...