LTE Multi Evaluation Measurement
R&S
®
CMW-KM5xx/-KS5xx
498
User Manual 1173.9628.02 ─ 16
Fig. 3-2: EVM window definition
The EVM window is centered on the cyclic prefix (CP) at the beginning of the SC-
FDMA symbol. Its length is specified in the standard, depending on the channel band-
width and the cyclic prefix type (see 3GPP TS 36.101, tables F.5.3-1 and F.5.4-1).
The CP is a cyclic extension of the SC-FDMA symbol. As a consequence the EVM for
a signal with good modulation accuracy is expected to be largely independent of the
EVM window size. Differences between EVM
h
and EVM
l
arise e.g. due to the effects of
time domain windowing of FIR pulse shaping.
Fig. 3-3: Cyclic prefix
EVM window length settings
Use the settings in the "Config... > Measurement Control > Modulation > EVM Window
Length" section to adjust the length of the EVM window (see
on page 556). The minimum value of 1 FFT symbol actually corresponds to a window
of zero length so that EVM
h
= EVM
l
.
3.2.2 LTE RX Tests
RX tests can be carried out in parallel to the TX tests. The following sections describe
how to perform LTE BLER tests in non-signaling mode, using the LTE "Multi Evalua-
tion" measurement. In signaling mode (combined signal path) use the BLER measure-
ment provided by the LTE signaling application.
General Description
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