Rohde & Schwarz CMU-K20, Руководство по эксплуатации

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CMU-K20/K21/K22/K23/K24
Signalling: Setting up a Connection
1115.6088.12 4.89 E-12
GSM Mobile Tests (Signalling)
The structure of this section is based on the configuration and measurement groups defined in function
group
GSM400/850/900/1800/1900-MS Signalling
. The menus are described in the following order:
1. Call setup to the mobile station
(Connection Control – Connection)
2. Overview of measurements and global settings
(Overview)
3. Measurement menus
(Power, Modulation, Spectrum, Receiver Quality):
Purpose of the
measurements and relation to the test specifications and conformance requirements, description
of measurement results, specific measurement configurations
4. General device configurations
(Connection Control)
The most important menus within function group
GSM400/850/900/1800/1900-MS Signalling
are
shown in an overview at the end of chapter 3 in the present GSM manual.
A lot of menus and controls are identical in the two test modes
Signalling
and
Non Signalling
. In this
chapter, these menus are only presented with a summary explanation; the detailed description can be
found in the section
GSM400/850/900/1800/1900-MS Non Signalling
.
Setting up a Connection
(Popup Menu Connection Control – Connection)
The menu group
Connection Control
controls the signalling procedures (call setup and release,
services, signalling parameters) and configures the inputs and outputs with the external attenuation
values and the reference frequency.
The term signalling denotes all procedures that are necessary for call setup and release and for control of a
connection in the mobile radio network. In the case of GSM mobile tests, a distinction is made between five
different signalling states:
Signal Off
CMU transmits no signal
Signal On
CMU transmits a GSM control channel signal to which a mobile station can synchronize
Synchronized
Synchronization with the mobile station and location update performed
Alerting
Mobile is being called by the CMU (after location update or without location update)
Call Established
Call to mobile station established
A number of control commands which can be initiated both by the CMU
(Connect Mobile, Mobile Terminating Call)
and by the mobile station
(Call from MS, Mobile Originated Call)
switch between these states (the dashed lines in
Fig. 4-41
denote processes initiated by the mobile station).
A lot of applications within the function group
GSM400/850/900/1800/1900-MS Signalling
are only possible or
useful in a particular signalling state (for example, handover between various networks requires a connection
between CMU and mobile station, i.e. it is only possible in the
Call Established
state). Accordingly, the possible
functions of menus vary depending on the present signalling state. For reference see the
Sig. State
field in the
command tables in Chapter 6.
The purpose of the
Signalling
test mode is to perform transmitter and receiver tests with an existing call
(or data transfer) connection between the CMU and the mobile. Therefore the menus for setting up a
connection (
Connection Control – Connection)
appear immediately after the function group and mode
GSM400/850/900/1800/1900-MS Signalling
is activated
.
Besides, all the tabs in the
Connection Control
menu can be called up by pressing the
Connect. Control
softkey at the top right in every measurement
menu. They are linked with each other via the hotkey bar at the lower edge of the screen. Pressing the
Escape
key closes the active
Connection Control
menu and re-activates the underlying measurement
menu.
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