NB-IoT NPRACH Measurement
R&S
®
CMW-KM300/-KS300
329
User Manual 1178.5689.02 ─ 06
After connecting your NB-IoT UE to the R&S
CMW, you have to adjust at least the fol-
lowing measurement settings to the properties of the analyzed NPRACH signal:
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Analyzer "Frequency"
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"Expected Nominal Power"
Optionally "User Margin" and "External Attenuation (Input)"
Recommended values:
–
"Expected Nominal Power" = peak power of the UE signal during the measure-
ment
–
"User Margin" = 0 dB
The smallest possible value of the "Expected Nominal Power" plus the "User Mar-
gin" ensures the maximum dynamic range.
●
"NPRACH Preamble Format"
The default trigger settings are often suitable.
4.2.3
Defining the Scope of the Measurement
A single-shot NB-IoT NPRACH measurement comprises one measurement cycle
which comprises a configurable number of measurement intervals (statistic count).
In this context, two types of result views must be distinguished:
●
Single-preamble measurements
evaluate one preamble per measurement inter-
val. The related views display results for the current measurement interval (one
preamble). They also provide a statistical evaluation for the already measured pre-
ambles (e.g. average within measurement cycle, extreme value since start of mea-
surement).
Examples for single-preamble result views are "Error Vector Magnitude" and
"Power Dynamics".
●
Multi-preamble measurements
evaluate up to 32 consecutive preambles per
measurement interval. The related views present the results per preamble, for all
preambles of the current measurement interval. No statistical evaluation over sev-
eral measurement intervals is performed.
The preambles captured within one measurement interval are labeled 1 to n, with n
≤
32. Single-preamble measurements evaluate the preamble labeled 1.
The time between two preambles is configurable. If no preamble is found, the mea-
surement continues and there are no demodulation results for that label.
Examples for multi-preamble result views are "EVM vs Preamble" and "Power vs
Preamble".
The scope of the measurement is configured in section "Measurement Control" of the
configuration tree. The most important parameters are:
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General Description
深圳德标仪器
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