Rohde & Schwarz CMU-K20, Operating Manual

Page: 254 / 646

Signalling: Connection Control
CMU-K20/K21/K22/K23/K24
1115.6088.12 4.176 E-12
Signalling
Channel
Signalling Channel
determines which channel is used for signalling:
SDCCH
Signalling via
stand-alone dedicated channel:
Call setup to traffic
channel with an extra signalling channel (normal mode in the
network), duration 4 s to 6 s
FACCH
Signalling via
fast associated control channel:
Fast call setup
with signalling on traffic channel, duration 1 s to 2 s
NONE
No automatic connection setup: The mobile must be controlled
by means of an external test interface so that the CMU reaches
the
Call Established
state. This mode is analogous to
Reduced
Signalling
in packet data mode; see
Service Selection
softkey on
p. 4.192 . It is automatically activated if one of the (E)GPRS
traffic modes is selected
(see Traffic Mode softkey on p.
4.170
).
Remote control
CONFigure:NETWork[:CSWitched]:SMODe:SCHannel
Loop Command Loop Command
determines in which cases the close loop command
(CLOSE_TCH_LOOP_CMD) is sent to the mobile station. Closing the loop causes
the mobile station to return all received bits to the CMU. In the case of an open
loop, the mobile station does not send back anything. Most but not all mobiles
require a test SIM card to enter the loopback mode.
Enable
If the test set sends a pseudo-random sequence (PSR2E9-1,
PSR2E11-1, PSR2E15-1, PSR2E16-1, e.g. for
Receiver Quality
measurement), the loop is closed. If no pseudo-random
sequence is sent
( Bit Stream = ECHO, Loopback, Handset;
see
p. 4.171
)
, the loop is left open. The loop type defined via
Loop
(see p. 4.156 ) is used.
Disable
The CMU sends no close loop command (not even if a
Receiver
Quality
measurement is active). Exception: See below.
Sensitivity
The loop is closed only for
Receiver Quality
measurements. The
loop type defined via
Loop
(see p. 4.156 ) is used.
Note: If a data connection with pseudo-random data is active
(see
Traffic
Mode
softkey on p. 4.170 )
, then the loop command is always closed.
A closed loop is a prerequisite for a receiver quality test (bit-error-rate measurement).
However, it can be useful for transmitter measurements as well, since it permits to obtain a
pseudo-random-modulated transmit signal from the mobile in an easy way. If the CMU
transmits a pseudo-random modulation, the close loop command also causes a pseudo-
random modulation of the signal to be returned by the mobile station.
Remote control
CONFigure:NETWork[:CSWitched]:SMODe:LCOMmand
Requested
Mobile Data
Requested Mobile Data
determines which signalling parameters of the mobile
station are requested and displayed:
IMSI Request
Request of the international mobile subscriber identity
(On)
or no
request
(Off)
.
IMEI Request
Request of the international mobile station equipment identity
(On )
or no request
(Off)
.
Authentication
Switching the authentication request
On
or
Off
.
Request
Handover
Request to determine whether the mobile station can hand over
Request
to another GSM radio network (e.g. GSM1800, GSM1900)
(On)
or not
(Off)
. Dual band handover is always possible.
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