LTE PRACH Measurement
R&S
®
CMW-KM5xx/-KS5xx
742
User Manual 1173.9628.02 ─ 16
The R&S
CMW can auto-detect the location of the used resource blocks in the fre-
quency domain ("PRACH Frequency Offset"). It can also auto-detect which of the 64
preamble sequences defined by the parameters above is used ("Sequence Index").
Non-matching "Measurement Control" settings generally result in large EVM results
and/or a "Sequence Correlation" much smaller than 1 (result presented in each view).
The default trigger settings are usually appropriate and don't need to be modified, see
chapter 4.2.5, "Trigger Modes"
4.2.3 Defining the Scope of the Measurement
A single shot LTE PRACH 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:
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"Single Preamble" measurements evaluate one preamble per measurement inter-
val. The related views display results for the current measurement interval (one
preamble) and provide a statistical evaluation for the already measured preambles
(e.g. average within measurement cycle, extreme value since start of measure-
ment).
Examples for "Single Preamble" result views are "Error Vector Magnitude" and
"Power Dynamics".
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"Multi Preamble" measurements evaluate up to 16 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
≤
16. "Single Preamble" measurements evaluate the preamble labeled 1.
A sequence of preambles to be captured in a single measurement interval must
have a periodicity of 20 ms, i.e. each 20 ms a preamble starts.
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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Example: Limited sequence of preambles with increasing power
Scenario: A sequence of 10 preambles with increasing power shall be measured. Main
result of interest is the TX power of the individual preambles (verify correct ramping up
of preamble power by UE).
Used view: "Power vs Preamble"
Settings: statistic count = 1, number of preambles = 10, repetition = single shot
General Description
深圳德标仪器
135-1095-0799
