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simmus0300
2009-07-04, 02:10 PM
I want to discuss two questions:-
(1) sometimes during drivetest it is seen that a cell A attempts Handover to a cell B which is not the neighbour of cell A. Why it is so?

(2) When Handover(O/G H/O) fails from a cell A to its neighbour cell B then does it means H/o definition is defined in Cell A but not in Cell B?

Aircom
2009-07-04, 04:41 PM
this question already postedf in forum just make search and you find response

thanks

RF engineer
2009-07-04, 08:16 PM
hi
For HO fail there are alot of reason you should checkd but let your case
for case 1 it is impoosible to have HO command( or attempt) for cell not defined you can see in the neighbor list but never send HOCMD may be you have COBCCH/BSIC because of that system recognized as neighbor .
for case 2 may be there is interference,coverage problem ,congestion ,Hardware,,,,,,,,,,,,)
it is better to check you log file carefully in order to find the problem.

simmus0300
2009-07-04, 09:03 PM
hi
For HO fail there are alot of reason you should checkd but let your case
for case 1 it is impoosible to have HO command( or attempt) for cell not defined you can see in the neighbor list but never send HOCMD may be you have COBCCH/BSIC because of that system recognized as neighbor .
for case 2 may be there is interference,coverage problem ,congestion ,Hardware,,,,,,,,,,,,)
it is better to check you log file carefully in order to find the problem.
I am not agree with you on answer of query 1. During drive test i have seen many times that H/O fail with a cell that is not defined in the neighbour. Why it is so?

venom
2009-07-04, 09:08 PM
I want to discuss two questions:-
(1) sometimes during drivetest it is seen that a cell A attempts Handover to a cell B which is not the neighbour of cell A. Why it is so?

(2) When Handover(O/G H/O) fails from a cell A to its neighbour cell B then does it means H/o definition is defined in Cell A but not in Cell B?

You need to verify the BSS database before doing a drive test, at least see what is defined so that u know the behaviour of the cell !!

1. Cell A will never attempt HO to cell B if it is not defined in BSS Database. If you are looking at TEMS Neighbor list then don't rely on it because TEMS can not show all the neighbor list in 1 window. Again verify it from BSS Dum-ps !!

2. if handover fails from Cell A and Cell B (considering the neighbor is defined) then there could be several reasons.

1. Check the LAC information at BSS Database, See if the neighbor is defined as internal or external.
2. Check the Quality, Adjacent Channel.
3. Check the RxLev, Handover Margin etc.
4. Check the cell KPIs, if the HOSR is bad then look for Intra Cell Handover, if the attempts are too high in its own cells then look for Swap as welll.

Brother there could be many reasons, again i can not tell you everything but as an optimization engineer u need to look for the possibilities. !!!

neerajsyal
2009-07-04, 09:25 PM
some time it happens that same site with different arfcn & bsic appears in the neighbour list twice or thrice
in the neighbours list in TEMS.WHY?

how to check the sites due to which handover has failed?

what is handover margin?

how to chaeck that handover has occurred to suitable neighbour or not?

kindly give me reply of it .thanks a lot.

MINTO
2009-07-05, 02:47 AM
You need to verify the BSS database before doing a drive test, at least see what is defined so that u know the behaviour of the cell !!

1. Cell A will never attempt HO to cell B if it is not defined in BSS Database. If you are looking at TEMS Neighbor list then don't rely on it because TEMS can not show all the neighbor list in 1 window. Again verify it from BSS Dum-ps !!

2. if handover fails from Cell A and Cell B (considering the neighbor is defined) then there could be several reasons.

1. Check the LAC information at BSS Database, See if the neighbor is defined as internal or external.
2. Check the Quality, Adjacent Channel.
3. Check the RxLev, Handover Margin etc.
4. Check the cell KPIs, if the HOSR is bad then look for Intra Cell Handover, if the attempts are too high in its own cells then look for Swap as welll.

Brother there could be many reasons, again i can not tell you everything but as an optimization engineer u need to look for the possibilities. !!!well i dont agree with point1..if cell A have get a handover failure on cell B, 1 reason can be some cell c is defined as a neighbour with same bcch bsic of cell B,i have solved many problem with this reason

venom
2009-07-05, 07:00 AM
well i dont agree with point1..if cell A have get a handover failure on cell B, 1 reason can be some cell c is defined as a neighbour with same bcch bsic of cell B,i have solved many problem with this reason

Read my complete post before making a comment yadav !!

I said check the Database, it doesnt matter if you have defined the Cell C with the Same BCCH and BSIC but the Cell ID, Lac information, infact in SIEMENS the cell id is defined with BTSM/BTS will be different !! You need to check the Database, BCCH and BSIC can be same but CELL ID can never be same !!!

You need to check the Database, if the Cell is not defined in Neighbor then the Handover will never take place !

RF engineer
2009-07-05, 10:09 AM
I am not agree with you on answer of query 1. During drive test i have seen many times that H/O fail with a cell that is not defined in the neighbour. Why it is so?
May be you did not understand what i meant there is cell close to cell A with far cell having same BCCH and BSIC this that you see far cell and try to make HO attempt but will fail sure .
Be free for any comment .
BR

hassen
2009-07-05, 10:36 AM
hi
you can define ho single or both
as example single A to B but not B to A
both A to B and B to A
but never ho to cell not defined as neighbour

br hassen