System Overview
R&S
®
CMW500
79
User Manual 1173.9463.02 ─ 02
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In a single-ended receiver quality test, the received bit sequence is evaluated at the
DUT. The measurement requires a real-time or ARB RF generator; no R&S CMW500
measurement application is needed.
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In a loop test the DUT is commanded into an operating mode where it loops back the
received data. The R&S CMW500 demodulates the uplink (reverse) signal and com-
pares the received bits with the original pattern. The bit error rate is calculated,
assuming no transmission errors in the uplink. The loop test requires an RF generator
in combination with a measurement application. No signaling functionality is required.
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Signaling applications provide integrated receiver quality tests. The receiver quality
is assessed with an established network connection; the details are network-depend-
ent. The R&S CMW500 controls the DUT such that it can either loop back the received
data or send acknowledge (ACK) or not acknowledge (NACK) messages to indicate
whether it could successfully receive a data packet or frame.
The Bit Error Rate (BER) is defined as the percentage of bits that the DUT received in
error:
BER = <No. of Bits received in error> / <Total no. of bits> * 100 %
Similar definitions apply to the Packet Error Rate (PER), Frame Error Rate (FER) etc.,
refer to the relevant applications.
Receiver quality tests may be performed with channel-coded or uncoded signals ("raw
BER tests"). The R&S CMW500 provides loop tests and signaling tests for many network
standards.
4.4 Signaling Applications
While a signaling application is active, the R&S CMW500 transmits a downlink (forward
link) signal to which the mobile station under test can synchronize in order to establish a
network connection. With an established connection, the R&S CMW500 can exchange
control messages with the mobile, request the mobile capabilities, and perform various
TX and RX tests.
The R&S CMW500 supports signaling applications for various network standards. The
applications are similar in structure, however, the details of connection setup, the sig-
naling parameters, and the measurements which you can perform with an established
network connection depend on the standards. The following topics describe common
features of the signaling applications.
For a sample session refer to
chapter 3.2.3, "Performing Signaling Measurements"
4.4.1 RF Path Settings
The R&S CMW500 provides a number of settings that are very similar in different sig-
naling applications but can be configured independently. These settings control the rout-
ing of signals and the signal levels.
Signaling Applications
