- This topic has 10 replies, 1 voice, and was last updated 10 years, 2 months ago by Johny.
12th February 2011 at 12:18 #65763JohnyGuest
Hi Every one,
can you please tell me what is the main cause of call Drop on SD channel.
There is No congestion, No BSIC & BCCH Clash, No path Imbalance and HW issue.
Where this drop lie in SD Drop or TCH Drop.
How we can rectifies this drop.
Vendor Huawei.13th February 2011 at 00:23 #65764RexGuest
1. Are there both SD drop and TCH drop in the same time?
2. Are TCH drops occurring in the same TRX where SDCCH is declared or SDCCH drops in one TRX and TCH drops in another? If in the same TRX then the issue is that TRX.
3. Now, what is the cause? Radio, BSS, TC drops?
4. What is interference on Idle timeslots, what is percentage of UpLink quality HO (this is to ensure you might have interference in uplink)?
Rex14th February 2011 at 06:28 #65765johnyGuest
we are using this formula for TCR
is that we including Call Drop on SD Channel in this formula
TCR Formulae :
ZTR304A = CM33/(K3013A+CH323+CH343-CH313-CH333)
only SD drop due to poor level & Quality in uplink.
I think for TCR,
SD channel should not comes in picture but durring immediate assignment it may comes.
please share yours view.14th February 2011 at 09:19 #65766JosueGuest
Problem indication:drop due to bad quality
. Interference-co-or adjacent interference
downtilt interferer cell or cells
Problem indication-Drop due to other reason
since there is no urgent conations but the call is dropped its hard to find the reason
. Generally drops due to other reason indicate a non RF problem
.dTRU or dRU hardware problem
.wrong definition of call in MSC BSC
.Wrong LAC definition in MSC14th February 2011 at 14:41 #65767JohnyGuest
I am getting immediate assignment failure in network also on SDCH and TCH both. but for different cells and different Trx.
The counters are
1. R4400A:Attempted Immediate Assignments (SDCCH)(times)
2.R4400B:Successful Immediate Assignments (SDCCH)(times)
3.R4409A:Attempted Immediate Assignments (TCH)(times)
4.R4409B:Attempted Immediate Assignment Prodedures (TCH)(times)
can any boby
I am getting immediate assignment failure also on SDCH and TCH both. but for different cells and different Trx.
Can any body tell which KPI leads to stepped UP or Down for Immediate assignment failure15th February 2011 at 00:08 #65768RexGuest
Try to make Drive Test measurement in the areas covering from those cells in order to be sure about interference. Check RxQual, FER etc. In layer 3 messages check for reasons of call drop.
Regards,15th February 2011 at 04:49 #65769JohnyGuest
But Which KPI effected if we are getting immediate assignment failure?whats the couter for?15th February 2011 at 13:44 #65770JohnyGuest
Help Me15th February 2011 at 18:12 #65771BrotherGuest
hardware problem can be, congestion might, interference is also possible, if site is covering large area change rxlevaccessmin or tilt milt…15th February 2011 at 21:47 #65772RexGuest
KPI affected by immediate assignment failure is SDCCH success rate. Check threads regarding immediate assignment failure, for example thread=4091 or do search by topics you are interested.
Rex17th February 2011 at 09:28 #65773JohnyGuest
High utilization (above 60%) increased the call drop possibilities. AMR/FR tuned to 55%?