User Manual

ArchitectureNortel Networks Confidential 3–13
S8000/S8002/S8006 BTS Reference Manual
If a fault occurs, the switching matrix is designated as faulty and switch over is
triggered.
The cause can be pinpointed from among the following:
switching matrix
internal PCM bus
idle interface
transmission test interface
reception test interface
3.2.1.6 FH bus management
The FH bus is connected to various DRX (or e–DRX) units.
Configuration
FH bus management becomes involved when the BSC sends cell configuration or
radio transmission configuration messages.
The CSWM uses the cell configuration message to construct the internal tables
needed for FH bus management.
The radio transmission configuration message is used to send monitoring masks to
transmitters used to check for frequency collisions and the flags on FH input
Monitoring/defense
FH bus management receives the frequency collision and no FH bus flag messages
sent by transmitters on the O&M bus.
Frequency collision messages cause an event report to be sent to the BSC (messages
are correlated to avoid repetition).
No FH bus flag messages result in the following:
a DRX (or e–DRX) fault when all the DRXs (or e–DRXs) detect the same event
a DRX (or e–DRX) fault when one event is detected
3.2.1.7 Transmitter–oriented CSWM defense actions
The CSWM undertakes defense action when it receives alarm messages or when the
scanner no longer detects transmitter activity.
If the faulty transmitter was configured (BCCH), the BTS sends an event report with
impact to the BSC; otherwise, the event report is without impact.