Cambium Networks cnWave 5G Fixed, Руководство по эксплуатации и устранению неисправностей

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Troubleshooting cnWave™ 5G Fixed Platform of Products 29
Consider the following details:
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Rx Power – if the value shown is -120 dBm (default), then the CPE is not able to find the BTS
(wrong frequency or obstacle in the path). Ensure the path between the BTS and the CPE is
free of any obstacles. The cnWave™ 5G Fixed platform of products works only in Line of
Sight (LoS) environments.
A good value is around -40 dBm when a BTS-CPE link is well established. This is also
dependent on local regulatory requirements (EIRP).
Figure 20 shows the relationship
between the Modulation and Coding Scheme (MCS) levels and the corresponding value of
the CPE Rx Power.
Figure 20: CPE Rx Power vs MCS modes
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Error Vector Magnitude (EVM) – A good EVM must be in the range of -20/-25 dB. This
parameter is dependent on the modulation mode and less on the frequency and bandwidth.
You can monitor the changes of this parameter when the CPE is trying to attach. After a
little while, you can notice that the value keeps going up and down without settling to the
negative twenties value. This means that the CPE cannot see the BTS. That can usually be
due to an alignment issue or a frequency issue, but if they have the same frequencies and
that the CPE is close and loosely aligned, there is a hardware issue with the CPE (calibration
or hardware failure).
Figure 21 shows the relationship between the MCS modulation levels
and the corresponding EVM value.