General Description
R&S
®
CMW-KN5xx
11
User Manual 1176.7690.02 ─ 05
Fig. 3-1: Connecting an RF transmitter to the instrument
To test a MIMO 2x2 signal, connect only one transmit antenna at a time.
3.2 How to Measure a Downlink LTE Signal
After connecting your eNodeB to the R&S
CMW, you have to adjust at least the follow-
ing analyzer settings to the properties of the analyzed DL LTE signal:
●
Duplex mode
●
Analyzer "Frequency"
●
"Expected Nominal Power", (optional) "User Margin" and "External Attenuation
(Input)".
Recommended values: "Expected Nominal Power" = peak power of the signal dur-
ing the measurement; "User Margin" = 0 dB. The smallest possible value of the
"Expected Nominal Power" plus the "User Margin" ensures maximum dynamic
range.
For synchronization to the received signal and proper decoding, a number of "Mea-
surement Control" settings in the configuration dialog must be in accordance with the
measured signal. In particular, ensure that the following parameters match up:
●
"E-UTRA test model"
●
"Channel Bandwidth"
●
"Physical Cell ID"
With matching "Measurement Control" settings, the R&S
CMW is able to decode the
signal and to determine its frame, subframe and slot timing. No additional measure-
ment trigger is required (see
Non-matching "Measurement Control" settings generally result in large EVM results or
cause a synchronization error.
3.3 Defining the Scope of the Measurement
Standard 3GPP TS 36.141 requests a measurement duration of 10 consecutive down-
link subframes for all tests.
How to Measure a Downlink LTE Signal
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