WCDMA Signaling
R&S
®
CMW-KG4xx/-KM4xx/-KS4xx
27
User Manual 1173.9657.02 ─ 11
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a single option R&S CMW-KE400 "WCDMA Fading Profiles TS 25.101, excerpts"
2.2.7.1
Fading Simulator
Multi-path fading is an effect which occurs in real world situations. A signal sent from
the base station may take different routes (direct line of sight and/or reflected) and
reach the receiving antenna at different times leading to a sum of phase shifted and, if
the receiver is moving, frequency shifted signals.
The internal fading simulator supports propagation conditions defined in Annex B.2 of
3GPP TS 25.101 e.g. multipath, moving or birth-death propagations.
A faded signal has a higher crest factor than an unfaded one. In order to avoid distor-
tion, the baseband signal must be attenuated before entering the fading module, with
the necessary attenuation (insertion loss) depending on the selected fading profile.
In WCDMA signaling, the insertion loss at the baseband level can be calculated auto-
matically or set manually. It is automatically compensated on the HF level, which
implies a shift of the allowed DL power level range to the same extent, but in opposite
direction.
2.2.7.2
AWGN Generator
Additional White Gaussian Noise (AWGN) is typically modeled in receiver tests,
because it may lead to a decrease of throughput. The quality of the received signal is
affected by the ratio of the signal power to the surrounding traffic noise level (signal to
noise ratio). The modulated signals from neighbor cells simply appear as noise. This
effect is simulated by adding AWGN to the signal.
The internal fading module supports AWGN insertion with configurable noise level.
Insertion loss at the baseband level is calculated and compensated automatically at
the HF.
The properties of the AWGN interferer comply with the requirements of 3GPP TS
34.121, section 7.1.2 (minimum bandwidth 5.76 MHz, flatness less than ±0.5 dB, peak
to average ratio at a probability of 0.001 % above 10 dB). It is needed for many of the
performance tests and support of RRM tests described in 3GPP TS 34.121.
AWGN insertion via the signaling unit is disabled for fading scenarios (see
2.2.8 Connection States
The UMTS core network consists of two service domains, the Circuit Switched (CS)
and the Packet Switched (PS) domain. You can set up a connection in the CS domain
and/or a connection in the PS domain. For supported connection types see
ter 2.2.11, "Connection Types"
The connection schemes for the CS domain and the PS domain are mostly independ-
ent from each other. The downlink signal generated by the R&S
CMW can emulate a
General Description
深圳德标仪器
135-1095-0799