Figure 30 Example Of A Spectral Sweep - WaveRider LMS4000 User Manual

5 Radio Network Planning
Figure 30 shows an actual spectral sweep, recorded using a spectrum analyzer as part of a
spectral survey, which shows the location of the cellular and paging transmitters in relation to
the ISM band. Note the relative levels of the interfering signals.
Cellular Radio
Transmitters
Cellular and paging systems in the bands adjacent to the ISM band can interfere with your
network and need to be addressed as follows:
• Identify and quantify all potential sources of interference by conducting and applying
the results of the spectral survey.
• If your CCUs or EUMs are close to cellular or paging sites, their receivers may be
desensitized by the high levels of the interfering transmitters, which can operate at
very high levels (100 W per cellular radio carrier, 1500W for paging transmitters). To
provide service to these EUMs, choose an operating frequency that is as far from
these cellular and paging transmitters as possible.
Try to assign frequencies that are not adjacent to the cellular or paging channels
identified in your serving area. Consider the scenario illustrated in
shown, a cellular tower is located in sector A of the LMS4000 radio network. Since
cellular frequencies are located just below the ISM band, a reasonable design
62
Figure 30 Example of a Spectral Sweep
ISM Band
Figure
APCD-LM043-4.0
Paging
Transmitters
31. As