ZXG10 BS21 (V2.2) Compact Outdoor BTS for GSM Maintenance Manual
140
Confidential and Proprietary Information of ZTE CORPORATION
Cell Carrier not Occupied
1.
Symptom
In dynamic data management, it is found this carrier is never occupied
by traffic, while the other states of it remain normal.
Use the test mobile-phone to conduct dialing test to the BS and we find
the frequency of the carrier cannot be occupied all the time.
The symptom mentioned above can be further subdivided into the
following cases:
i.
The carrier is not occupied. But after blocking the other TCH
carriers, the time slot of the carrier can be occupied normally.
ii.
The carrier is not occupied. But after the other TCH carriers are
blocked, the time slot of the carrier still cannot be occupied
normally.
iii.
The carrier is not occupied. But after other TCH carriers are blocked,
time slot of the carrier can be occupied transitorily and released.
2.
Source
Find the faults when observing the dynamic data management of the
background O&M system and try the dialing test.
3.
Related parts
The connection between the ETRM and the backplane, the RF cable of
the ETRM and the AEM, the RF cable of the dividers of the ETRM and of
the AEM and ETRM modules.
4.
Fault analyzing and locating
For the above three symptoms, the respective causes that make the
carrier not occupied are:
i.
According to the TCH assignment algorithm of the ZTE BSC, if a
time slot is assigned unsuccessfully, the priority of the time slot will
be decreased and other carrier slots will be firstly assigned in the
next assignment. The time slot can not be assigned until the traffic
gets heavier. So after other carriers are blocked, the time slot of
this carrier can be occupied normally.
ii.
The pin of the carrier is in poor contact with the backplane
(especially during BS debugging). At this time, the time slot of this
carrier can still not be occupied normally after the other TCH
carriers are blocked while the status observed from the dynamic
data management is normal.
iii.
The output power of this carrier or PA is lower than that of other
carriers. In this case, forcedly occupying the carrier’ time slot after
other carriers are blocked may cause the time slot of the carrier to
be occupied transitorily and then released.
