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Junior Member
Reputation: 6
High IRAT Failure in preparation phase
Hi experts,
In our E******* UTRAN we noticed a high preparation failure rate due mainly to the cause "RelocationFailureInTargetCNRNCorTargetSystem". I think that this is related to some capacity issues on 2G side, but from several flowcharts i saw the cause "Failure in the radio interface" sent in the "relocation cancel" message sent from the RNC, any idea about this??
Thanks
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2012-04-16 04:39 PM
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Re: High IRAT Failure in preparation phase
Yes it can be due to capacity issue or inconsistency, LAC,CI,BCCH BSIC etc
Check the inconsistencies then if its ok, then check the COngestion on TCH 2G
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Member
Reputation: 90
Re: High IRAT Failure in preparation phase
For everyone with the same problem, check the parameter Inter-RAT In BSC Handover Enable for 2G cells.
If this parameter is set = NO, will fail during the preparation of IRATHO to those cells.
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Junior Member
Reputation: 6
Re: High IRAT Failure in preparation phase
Actually i've got the failure per cell couple (3G/2G), i think if the parameter Inter-RAT In BSC Handover Enable for 2G cells will be set to "NO" we will have 100% failures which is not our case, since failure rate per cell couple is <>100%. Actually we detect 2G congestion, can anyone suggest some parameter setting instead of 2G capacity extension?
Knowledge is the true organ of sight, not the eyes. Kindly give me reputations.
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Junior Member
Reputation: 6
Re: High IRAT Failure in preparation phase
Actually i got a proposition to change the parameters usedFreqThresh2dEcno to -14 and usedFreqThresh2dRscp to -108 to change the compress mode trigger, but i'm not convinced about this proposition since the 3G neighbours should also be optimized. Any comments about this?
Knowledge is the true organ of sight, not the eyes. Kindly give me reputations.
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Member
Reputation: 295
Re: High IRAT Failure in preparation phase
Originally Posted by
Spider
Actually i got a proposition to change the parameters usedFreqThresh2dEcno to -14 and usedFreqThresh2dRscp to -108 to change the compress mode trigger, but i'm not convinced about this proposition since the 3G neighbours should also be optimized. Any comments about this?
Hi! I would first switch off all redirections to GSM (DR, LBHO, SBHO). Check also if all 2G->3G neighbours are defined properly. You may also enable HO from 2G to 3G. Then i would try to increase 3G coverage (PCPICH power, tilts).
Thanks and reps are appreciated.
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Junior Member
Reputation: 6
Re: High IRAT Failure in preparation phase
I checked again and remark that the RNC is sending many Relocation required to the same cell and all are failed. Consequently we have a high preparation failure rate since the procedure is triggered many times. Anyone who knows the set of parameters in E// RNC which are involved in this?
Knowledge is the true organ of sight, not the eyes. Kindly give me reputations.
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