LTE PRACH Measurement
R&S
®
CMW-KM5xx/-KS5xx
743
User Manual 1173.9628.02 ─ 16
Example: Statistical evaluation for preambles with constant power
Scenario: The EVM shall be measured for 100 preambles, so that the average and the
maximum value can be evaluated.
Used view: "EVM"
Settings: statistic count = 100, number of preambles = 1, repetition = single shot
4.2.4 Parallel Signaling and Measurement
The PRACH measurement can be used in parallel to the LTE signaling application
(option R&S CMW-KS500/-KS550). The signaling application emulates an LTE cell sig-
nal so that the UE tries to attach and sends random access preambles. These pream-
bles can then be measured using the PRACH measurement. You can configure the
signaling application so that it does not answer the received preambles.
To use both applications in parallel, the combined signal path scenario must be activa-
ted (see
"Scenario = Combined Signal Path"
on page 760). Most signal routing and
analyzer settings and some measurement control settings are then configured by the
signaling application. The PRACH measurement displays the corresponding signaling
settings instead of its own settings. These signaling settings can be configured both in
the measurement GUI and in the GUI of the signaling application.
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.
Whenever the combined signal path scenario is activated or the controlling application
is changed, the PRACH trigger signal provided by the controlling signaling application
is selected automatically as trigger source.
4.2.5 Trigger Modes
The LTE PRACH measurement requires a trigger event for each preamble 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 preambles. The default value of the mini-
mum trigger gap is usually big enough to ensure that the measurement is not re-
triggered within a preamble and small enough to ensure that the trigger system is
re-armed before the next preamble starts.
●
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.
General Description
深圳德标仪器
