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Chapter 8, Programming the Call Processing Subsystem
Description of the Call Processing Subsystem’s Remote User Interface
For forward control channel and forward voice channel signaling messages, the Call
Processing Subsystem provides the option of sending messages whose contents are built
using the rules and regulations specified in the applicable industry standard, or the control
program can define the message contents as desired. Having the capability to set the bit
patterns of the signaling messages sent to the mobile station gives the control program the
capability to test the robustness of the mobile station by introducing known errors into the
signaling messages. Once an error has been introduced the control program can monitor
the response of the mobile station.
Operational Overview
The Test Set simulates a cellular base station by using its hardware and firmware
resources to initiate and maintain a link with a mobile station. Unlike a real base
station, the Test Set has only one transceiver (its signal generator and RF/AF
analyzer) and can support only one mobile station at a time. This means that the
Test Set’s transceiver can be configured as either a control channel or a voice
channel, but not both simultaneously.
To establish a link with a mobile station the Test Set’s transceiver is configured as
a control channel. Once a link has been established and the user wishes to test the
mobile station on a voice channel, the Test Set sends the appropriate information
to the mobile station on the control channel and then automatically re-configures
its transceiver to the voice channel assigned to the mobile station. Once the voice
channel link is terminated, the Test Set automatically re-configures its transceiver
back to being a control channel.
Handoffs are accomplished in a similar manner. When a handoff is initiated while
on a voice channel, the Test Set sends the necessary information to the mobile
station on the current voice channel. At the proper time, the Test Set automatically
re-configures its transceiver to the new voice channel.
Figure 31 on page 428 illustrates the primary call processing functions available in
the Call Processing Subsystem. Each box represents a call processing state and
includes the measurement information available while in that state. Each box also
includes the name of the annunciator on the call processing screen that will be lit
while in that call processing state. Events which trigger transitions between the
various states are shown on the diagram. Events which are initiated from the Test
Set are shown in solid lines and events which are initiated from the mobile station
are shown in dashed lines.