Siemens problems

[stanislavangel777]

Hi !

Experts, please help me to solve problem:

My 2G network is working by Siemens vendor.

There are a lot of causes of Drop Calls:

1) MS in Active mode get the channel in GSM layer (900) with good RxLev.
2) When Rxlev <= -95 dBm in GSM layer the HO executes to DCS layer (1800) even if it with RxLev=-95 dBm too.
3) Then MS couldn't return to GSM layer even with very weak Rxlev on DCS layer (RxLev< - 100 dBm).
4) Then Call Drop happens.:(

I haven't manuals about HO featches, so can't understand why it happens.


Experts, give me an idea how to solve this problem.:confused:

Thanks a lot !!!

[hendral]

Hi !

Experts, please help me to solve problem:

My 2G network is working by Siemens vendor.

There are a lot of causes of Drop Calls:

1) MS in Active mode get the channel in GSM layer (900) with good RxLev.
2) When Rxlev <= -95 dBm in GSM layer the HO executes to DCS layer (1800) even if it with RxLev=-95 dBm too.
3) Then MS couldn't return to GSM layer even with very weak Rxlev on DCS layer (RxLev< - 100 dBm).
4) Then Call Drop happens.:(

I haven't manuals about HO featches, so can't understand why it happens.

Logical parameters of my network are in attachments.

Experts, give me an idea how to solve this problem.:confused:

Thanks a lot !!!

You want someone to help you but why you let us waste our 5 point. I dont understand your way ....

[stanislavangel777]

You want someone to help you but why you let us waste our 5 point. I dont understand your way ....

Hello, Hendral ! I'm a newcomer in this Forum. So I didn' t want to waste your points. I'll be carefuly last time.

My problem that I was working only with E*******, Nokia and a little Motorolla vendors. But it's hard to find manuals about HO algorithm for Siemens.

Hendral, thanks a lot !

[oswe]

Hello, Hendral ! I'm a newcomer in this Forum. So I didn' t want to waste your points. I'll be carefuly last time.

My problem that I was working only with E*******, Nokia and a little Motorolla vendors. But it's hard to find manuals about HO algorithm for Siemens.

Hendral, thanks a lot !


you are sure both adjacencies are correctly created ?
do you know if HCS is implemented ?
man you should get introduced to all HO features and parameters to solve this problem...

[junyian]

From the explanation, sounds like HO due to poor coverage to DCS, and DCS also have poor coverage and tries to HO back and fail?

[stanislavangel777]

you are sure both adjacencies are correctly created ?
do you know if HCS is implemented ?
man you should get introduced to all HO features and parameters to solve this problem...

Hi, Oswe! I try to investigate this problem:

1) HCS is implemented;
2) The parameter "HOM" (HO_Margin):
-- for GSM-->GSM HOM=69;
-- for DCS --> GSM HOM = 80 !!! :p;

I think, I've get the idea of the root problem. Now I'm investigating other features (Concentric Cells and so on). May be it'll be other parameters which create this problem.

The problem in my Network started after optimization by one of our contractor.:(

Dear,Oswe. what whould you check in this situation ? Thanks a lot.

[stanislavangel777]

From the explanation, sounds like HO due to poor coverage to DCS, and DCS also have poor coverage and tries to HO back and fail?

Hi, Junyian ! Yeah, It' look like this. I try to understand if this problem because of wrong HO_Margin (HOM) for relation DCS --> GSM.

Dear, Junyian. Have you idea of the reason of this problem?

Thank you for your help!

[junyian]

The higher HO margin does make it harder to handover from that cell. HOM value 80 corresponds to 17dB, while 69 is 6dB. But if that area have poor coverage, maybe you should concentrate on improving the dominance as a longer term measure? Changing the value back to 69 might just be a short term solution. I'm rather new to this so comments are welcome.

[stanislavangel777]

The higher HO margin does make it harder to handover from that cell. HOM value 80 corresponds to 17dB, while 69 is 6dB. But if that area have poor coverage, maybe you should concentrate on improving the dominance as a longer term measure? Changing the value back to 69 might just be a short term solution. I'm rather new to this so comments are welcome.

Perfect, Junyian !!!

I agree with you. That mustn't be only one reason for this problem. I'll investigate all features implemented in this Network and values of logical parameters. I'll tell you if it'll be some interesting, Junyian.

Thanks a lot !!!

[plannerguy]

Hi

please xheck the HO threshold for GSM to DCS ie HORXLVDLO and HORXLVDLI

Regards
Plannerguy

[stanislavangel777]

Hi

please xheck the HO threshold for GSM to DCS ie HORXLVDLO and HORXLVDLI

Regards
Plannerguy

Hi, Plannerguy !

The feature "Concentric Cell" is OFF.

I found some wrong in RXLEVMIN:

RXLEVMIN

DCS --> DCS 19 (-91 dBm)

DCS -->GSM 19 (-91 dBm) :mad:

GSM -->DCS 12 (-98 dBm) :mad:

GSM -->GSM 12 (-98 dBm)


I think RXLEVMIN must be :



RXLEVMIN

DCS -->DCS 19 (-91 dBm)

DCS -->GSM 12 (-98 dBm) :p

GSM -->DCS 19 (-91 dBm) :p

GSM -->GSM 12 (-98 dBm)

I'm investigating all other logical parameters....