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Auth or Depa rtme nt Upda te Time Appr over Title:
Gao Bo
Staff Number
40827
UMTS RNP
Product Family:
Wireless Performance & RNP & RNO
2010-06-01
Product Vension:
RNC R10B061
Analysis for Call Drop due to SRB Reset !RB Reset
Pheno The problem is that there are many sites have the problem of SRB reset menon and TRB reset increased. Descri ption: Alarm None Inform ation: Cause For this problem, we choose the top cells of the RNC ! and RNC ! to Analysi analy"e the reason of SRB # TRB reset. s:
From the analyses of the cell C$T and I%S, &e can 'now that () was doin* +S$- traffic .It did hard handover from one cell to another cell. Bt after hard handover completed, imminently, () did hard handover bac', this is the pin*/pon* phenomena. It is easy to reslt in radio lin' lost and the increase of TRB0SRB Reset.For the downlin' 1ality chan*ed so fast, it is abnormal. -nd this is sally becase that the C)223s parameter or cell3s covera*e is nreasonable. -nd the same phenomena also can find in the cells with I$ 4456 ,478, 95!5 ,9575,94! 9478. From the trace, we can see that the () hand over from cell 4456 to cell 4785 , bt after ! seconds, it delete the lin' of 4785. It is so fast, and the R2 was ot of synchroni"ation, then the call drop occrred.
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From the measre report, we can see that the cell 4785;SCR-5 ? has a better )C0N%, then the - event happened sccessflly.
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Bt after ! seconds, the )C0N% chan*ed so fast and the R2 of the cell 4785 was deleted.
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Then the R2 was ot of synchroni"ation. -nd the SIR/)rror vale of the (plin' is so bad. The call drop occrred.
-nd there are many pin*/pon* phenomena as below: From the trace 2013-1-31
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we 'now that the () hand over from 4455 to4456, then immediately, hand over bac' to 4455.It cost only or two seconds. This is nreasonable. It is easy to reslt in radio lin' lost.
From the C$T and I%S, we can find the other problem cased the call drop, for e@ample, the bad downlin' 1ality and the nei*hbor cell not confi*red. If in some position the downlin' 1ality is bad, and the nei*hbor cell has not been confi*red, the call drop will occrred easily. ? Nei*hbor cell not confi*red For cell 4456, from the I%S trace, we can see that it has the problem of nei*hbor cell not confi*red. Ast as the cell 9> we analy"ed before. From the I%S, the plin' has been ot of synchroni"ation, and from the RRC<)-SRRT, we can see that the downlin' of cell 4456;SCR-
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!? $ownlin' bad For the cell 9445, it has many times of TRB reset and (( No reply, we have collected the lo*s to analy"e the reason. There are many call drop procedres as below: -fter the () *oes to F-C+ then call drop occrred.
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&e can see that the () want to *o to the $C+, bt From the RRC<)-SRRT we can find the )C0N% is bad now which means the downlin' is bad, and the () wold not receive the messa*e of RRCRBR)CF. Then the Call $rop occrred. -nd from the RRC<)-SRRT, we can3t see any other cells that the () can detected.
-nd we can see as below: If the downlin' is *ood, the () will *o to $C+ sccessflly. 2013-1-31
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It can be solved by optimi"in* the parameter and the covera*e of the networ'. Handli ng Process
:
The pin*/pon* phenomena is abnormal, and the lo*s shows that the call drops were de to the covera*e of cells and the parameters confi*red.
Sugges tions and summa ry: Attach ments
: Relate d docum ent link :
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