SQI problem in GSM

[cm_rao29]

Hi Experts,

I am facing some problems with SQI in the network. could someone advice what influence the SQI. or anyone having any documents related to it? or anyone faced this problem before.. what actions were taken? The customer is very hard to be convinced, they wants a clear explanation. Please help.
Thanks

[rheyra]

Hi cm_rao29,
There can be some reasons for your problem, and since you didn't mention more detail about your network configuration / parameters, so I will make this general:
- SQI depends on speech codec used (either it uses FR, HR, AMRFR, AMRHR). So if you change your halfrate parameters, for sure your SQI figure will be changed
- SQI also depends on interference level in your network. The worse youe have, SQI will degrade also. For BBHOP network, please do a good frequency plan. And for SFH network, please make sure all hopping parameters well done, include HSN, MAIO, MALIST, etc. And special for SFH network, be aware about your coverage, e.g. in SFH 1x1 or 1x3, even you have good HSN plan, but cell will suffer of interference because of overshooting of same sector different site.
Hopefully clear my friend.

BR//Rheyra
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Hi Experts,

I am facing some problems with SQI in the network. could someone advice what influence the SQI. or anyone having any documents related to it? or anyone faced this problem before.. what actions were taken? The customer is very hard to be convinced, they wants a clear explanation. Please help.
Thanks

[cm_rao29]

Hi Rheyra,

well thank you for your fast response. Appreciate it very much.
the problem is, the customers network here having both BB and SFH. and also they have DTX enable at certain area and disabled at other areas. now we are facing sqi not meeting the target for single site verification for almost 80% of the sites.Now the customer is requesting for a documentation on the recommendation proposed. we are facing a lot of problem convincing the customer to accept our suggestions.

Thank you.

[rheyra]

Hi cm_rao29,
1. How about half rate parameters? is it activated? And how about AMR, is it activated both HR and FR? How about EFR, is it used there?
2. How is traffic? high traffic and blocking? In high traffic, then half rate will be used, and for sure, SQI will be lower than FR.
3. Your 80% un-passed SQI sites: in SFH sites (what is your SFH type?), you have to do mostly coverage adjustment (antenna tilting and reorientation). For BBHOP, please do frequency retune for problematic spots.
Can you give your SQI figure (per site)?
BR//Rheyra

Hi Rheyra,

well thank you for your fast response. Appreciate it very much.
the problem is, the customers network here having both BB and SFH. and also they have DTX enable at certain area and disabled at other areas. now we are facing sqi not meeting the target for single site verification for almost 80% of the sites.Now the customer is requesting for a documentation on the recommendation proposed. we are facing a lot of problem convincing the customer to accept our suggestions.

Thank you.

[RF engineer]

In huawei i faced this problem and when checked it was problem due HW problem in BSC(GUIOB) boards and when moved from this board to other board it is Ok and there is also board in MSC related to speech .
I hope it helps you

[cm_rao29]

Hi Rheyra,

well, for HR and FR and EFR are enabled in the network.
the traffic is depending on the busy hours, sometimes drive test is done during busy hours.

Just wondering, how must would it effect if the call is in EFR??

SQI will ranges:

0-17 =7.8%
17-22 =4.7%
22-30 =87.5%

the target is 95%

the equipments are Huawei BSC 32 and BSC6000.

i am not sure of SFH type? can u explain

and frequency tuning is on going...

thank you

Hi cm_rao29,
1. How about half rate parameters? is it activated? And how about AMR, is it activated both HR and FR? How about EFR, is it used there?
2. How is traffic? high traffic and blocking? In high traffic, then half rate will be used, and for sure, SQI will be lower than FR.
3. Your 80% un-passed SQI sites: in SFH sites (what is your SFH type?), you have to do mostly coverage adjustment (antenna tilting and reorientation). For BBHOP, please do frequency retune for problematic spots.
Can you give your SQI figure (per site)?
BR//Rheyra

[cm_rao29]

Hi RF Engineer,

Could you please share, how can we check on the HW problem in BSC(GUIOB) boards?? Can we check/differentiate AMR call at different GEIUB board??

are there any statistical data we can find out for this problem?

Thank you.

In huawei i faced this problem and when checked it was problem due HW problem in BSC(GUIOB) boards and when moved from this board to other board it is Ok and there is also board in MSC related to speech .
I hope it helps you

[RF engineer]

There is no stat just you can do drive test during drive test you can see yo have good Rx level,C/I and Rx Quality but SQI is bad so in this case it shows that yo have problem on the port for this site connected to BSC just swapped into other port you can make drive test again. if it does not come out any thing still you have Problem got to MSC part that as i remember there is board call GOPT i am not sure you can check .
BR

[Nemer]

SQI parametr depends on the used codec.
HR SQI=21
FR SQI=27
EFR SQI=31
AMR HR SQI=27
AMR FR SQI=30
These are sizes at normal RF conditions.

[rheyra]

Hi,
Just want to do a correction for following statement:

HR SQI=18
FR SQI=21
EFR SQI=30
AMR HR SQI=27
AMR FR SQI=30

BR//Rheyra

SQI parametr depends on the used codec.
HR SQI=21
FR SQI=27
EFR SQI=31
AMR HR SQI=27
AMR FR SQI=30
These are sizes at normal RF conditions.