Fading Simulation
SMIQ
1125.5555.03
2.72
E-9
2.9.3
Correlation between Paths
Fading processes of different paths normally do not depend on statistical processes. However, it is
possible to set a correlation of paths 1 to 6 with paths 7 to 12 in pairs. To set the correlation, a synchronous
signal processing is required for the two fading options which involves the following restrictions:
•
The correlation is always reciprocal, ie if path 1 is correlated with path 7, path 7 is also correlated
with path 1 (CORR PATH).
•
The following parameters of the two paths have to correspond:
- Fading profile PROFILE
- Doppler parameter SPEED or DOPPLER FREQ
- Magnitude of correlation coefficient COEFF
•
The following equation applies to the phase of the correlation coefficient and thus to the phase shift
between the correlated paths:
ϕ
12
= 360
°
-
ϕ
21
•
The parameters for Log Normal fading have to correspond for correlated paths.
All parameter adaptations due to the limitations mentioned before are automatically performed by SMIQ.
Note:
After setting all parameters, the two fading options have to be synchronized by RESET and
then by RUN.
2.9.4
Menu FADING SIM
Fig. 2-38
Menu FADING SIM with submenus
FADING SIM
Selection of fading simulator mode.
STANDARD FAD
"Normal“ mode with 6 paths (with option SMIQB14) or 12
paths (with SMIQB14 and SMIQB15), time resolution 50 ns.
FINE DELAY
Mode with fine time resolution. Two paths are possible for
each option (SMIQB14 / SMIQB15). The system bandwidth
of the paths is limited to 4.6 MHz; this is sufficient for 3GPP
with 3.84 Msymb/s. Time resolution is 1 ns.
MOVING DELAY
Mode with 2 paths, one with a fixed delay, the other with
a delay varying sinusoidally. This corresponds to test
case 3GPP, 25.104-320, Annex B3.
BIRTH-DEATH
Mode with 2 paths with a delay randomly varying within a
time range.
Note:
The modes FINE DELAY, MOVING DELAY, BIRTH-DEATH are
possible only if software option SMIQB49 is built in.