Chapter 6 - Troubleshooting
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5.
The fault locating flow is as shown in Figure 82.
F
I G U R E
8 2
F
A U L T
L
O C A T I N G
F
L O W
C
H A R T O F
S D C C H
B
E I N G
O
C C U P I E D T O O
L
O N G
Start
Whether there are too
many short messages
Add configuration of the
SDCCH channel
Add CRH value and
configuration of the
SDCCH channel
Whether the traffic is
too centralized
Adjust T3122 and T3212
timer and parameters that
affect C2 value
Check whether the
T IC DIP switch is
correct
Correctly set the DIP
switch
YES
NO
YES
YES
NO
YES
Replace the T RM module
NO
NO
Whether SDCCH
congestion is solved
NO
YES
Conduct signaling tracing
and re-locate the fault
End
Remove the transmission
fault
YES
NO
Whether it is due to too
frequent location updates
at the LAC border
Use the bit error tester to
measure whether there are
bit errors in transmission
6.
Troubleshooting
i.
Judge whether too many short messages cause SDCCH to be
congested. If yes, adjust the ratio of SDCCH with TCH and add
SDCCHs according to the traffic of TCH. For example, configure 8
SDCCH/8 sub-channels for 2 TRXs, and configure 8 SDCCH/8 sub-
channels and 4 SDCCH/4 sub-channels for 3 TRXs.
ii.
Judge whether the SDCCH congestion is caused by the LAC border.
If yes but congestion is not severe, increase the CRH parameter
(cell reselection hysteresis) to 6 or 7 (the reselection hysteresis
level is 12 dB or 14 dB). That is, only when the signal level of the
adjacent cell (the location area is different from the current area) is
