Chapter 6 - Troubleshooting
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¾
Disconnect the inlet and the outlet of E1 at the BTS side to see
whether the red SYN light in CMM is always on. If not, replace the
CMM module.
¾
Self-loop E1 line at the BTS side to observe the status of the red
SYN light in CMM. If it is always on, replace the E1 interface line of
the set bottom. If it does not work, replace the CMM. If it is not on,
the inlet and outlet of BTS E1 are normal. Proceed with next step to
check whether transmission faults occur.
¾
Inquire the transmission equipment room whether transmission
alarms occur. Check whether the transmission grounding is good
enough. Test the transmission bit error when necessary.
iv.
Under the most unfavorable conditions, replace the CMM backplane.
7.
Precautions
Make sure to self-loop the E1 line to the BSC through the transmission
equipment at the BS.
MS Signal is not Stable in Idle State
1.
Symptom
In idle state, the receiving signals of mobile phones fluctuate.
Sometimes signals suddenly disappear and appear again after a
moment.
2.
Source
Faults occur in dialing.
3.
Related parts
The location of the mobile phone, reselection parameter setting, ETRM
and AEM modules.
4.
Fault analyzing and locating
Without considering the quality and unstable performance caused by
the long use of the mobile phone, the change of the receiving signal
level of the mobile phone reflects the change of the local wireless
signal intensity. The factors that influence the wireless signal intensity
of a place include:
i.
Landform.
ii.
Unstable BS transmission equipment. For example, when the ETRM
PA bearing the BCCH frequency works unstably or the RF
connection from ETRM to AEM is unreliable, the transmission power
of the ETRM will be unstable which will result in the unstable phone
signal.
iii.
Cell reselection leads to the change of signal receiving intensity of
the mobile phone.
