LTE SRS Measurement
R&S
®
CMW-KM5xx/-KS5xx
818
User Manual 1173.9628.02 ─ 16
To configure these settings via remote commands, the commands of the signaling
application must be used. For a command mapping table, see
The most important signaling parameters not relevant for standalone measurements
can nevertheless be configured both in the measurement GUI and in the GUI of the
signaling application. In the measurement GUI they can be accessed via hotkeys.
5.2.4 Trigger Modes
The LTE SRS measurement requires a trigger event for each SRS symbol to be mea-
sured. It can be performed in the following trigger modes:
●
IF Power (default mode): With an internal IF power trigger, the measurement is trig-
gered by the power ramp of the received SRS symbol. The default value of the
minimum trigger gap is usually big enough to ensure that the measurement is not
re-triggered within an SRS symbol and small enough to ensure that the trigger sys-
tem is re-armed for the next measurement interval.
●
External Trigger A/B: External trigger signal fed in via TRIG A or TRIG B on the
rear panel of the instrument.
●
Additional trigger modes: Other firmware applications, e.g. the LTE signaling appli-
cation (option R&S CMW-KS500/-KS550) or the GPRF generator may provide
additional trigger modes. Refer to the documentation of the corresponding firmware
application for a description of these trigger modes.
chapter 5.3.2.3, "Trigger Settings"
5.2.5 Limit Settings and Conformance Requirements
Conformance requirements for LTE transmitter tests are specified in 3GPP TS 36.521,
section 6, "Transmitter Characteristics".
The following section gives an overview of the SRS measurement limit settings and the
related test requirements.
5.2.5.1
Power Dynamics Limits
Transmission at excessive uplink power increases interference to other channels while
a too low uplink power increases transmission errors. For SRS transmission 3GPP
defines a time mask to verify the UL power while an SRS symbol is transmitted (ON
power), the UL power in the adjacent SC-FDMA symbols (OFF power) and the power
ramping in between.
The ON power is specified as the mean UE output power over the SRS symbol(s),
excluding transient periods of 20 μs. For the OFF power the mean power has to be
measured both in the preceding symbols and in the subsequent subframe, excluding
transient periods of 20 μs.
The following figures provide a summary of the time periods relevant for ON and OFF
power limits for FDD and TDD. The transient periods between the two TDD SRS sym-
General Description
深圳德标仪器