SDCCH Cong

[Aminoo]

Salam Team

Please your help for this case, i have some sites which they have a very high SDCONG (CNRELCONG), due to intermittence 3G sites(3G not stable),

I have added some SDCCH in CHGR1 but it causes some drops, so it affect the performances.

If there is some parametters to change, to avoid the drop caused by the modifications (SDCCH added in CHGR1)

Thank you for your help

[iamsasuke]

Hi,

Please check your TCH or transcoder congestion.
CNRELCONG could be an indicator for both SDCCH congestion/SDDROP caused by TCH/transcoder congestion.

tnx,

[oucht79]

Dear check the cause for the service request, if it's due to location update it's means when the 3G sites fluctuate it cause high location update, you can change the parameter for 2G 3G cell reselection to push more traffic to 2g under the area where you are facing 3g sites fluctuatuion.
thx

[Aminoo]

Hi Dear,

Ok, and thanks for your response, il already have this information, SDCCH cong and drops due to location update. you said that i can change the parameter for 2G 3G cell reselction to push more traffic on 2G, how it can be done given that i'm under E******* technology.

Thanks a lot

[oucht79]

Check the below parameters for e*******
QSearchI=7
FddQoffset= 0 You check and tune this parameter
FDDQmin= 3 (-8) or 5 (-10)

[Aminoo]

Hi,

here what i get from printing on FDDQMIN:


<RLSUP:cell=XXXXXXA;
CELL SYSTEM INFORMATION UTRAN DATA


CELL
XXXXXXA


QSC QSCI QSI FDDMRR FDDQMIN FDDQOFF SPRIO FDDQMINOFF FDDRSCPMIN
15 0 7 0 6 0 YES


FDDREPTHR2


END

So here my question, if i change the FDDQMIN (and i will go to sever change) =1, is this will affect also the performances on the neighbors cell, or just the cell on question.

Thanks

[Aminoo]

Hi,

Any suggestion ?

BR

[oucht79]

Hi
Suggestion already provided.
QSearchI
FddQoffset
FDDQmin

[Aminoo]

Hi oucht79 (http://www.finetopix.com/member.php?20204-oucht79)

yes i check all those parameters, but my question it was about FDDQMIN: If i change it in one cell, the perfrormaces of the sites around the site that i have change the FDDQMIN will be affected or not ?

Thank you for your help

[oucht79]

Hi,
You have to change it in all neighbors cells of the 3G unstable site
BR

[hpdefalcon]

QsearchI = 7 (always) maybe conflict with sRatsearch too low (-18dB)???

[ulhwbest]

Hi,

For SDCCH Congestion (high CNRELCONG), may I suggest you configure additional static SDCCH on CHGR 0, since this channel group uses the BCCH Frequency.
Assume that the frequency allocation for BCCH is clean meaning no frequency collision (co-channel or adjacent channel).

Parameters:
Verify if ACSTATE is set to ON, this is the parameter that relieves SDCCH Congestion. - Adaptive Configuration state.
You may also check SLEVEL and STIME.

Regarding the SDCCH drop you mentioned, check the SDCCH drop reasons - bad quality, low signal strength, excessive timing advance, others (could be transmission related or congestion on TCH).
Now in the case that SDCCH channel can no longer be added on CHGR 0, once you configure additional SDCCH channel on CHGR 1 then you had counts of SDCCH drop, here are my suggestions:
1. First verify the drop causes:
a. Bad Quality
Verify the frequency allocated to see if there's any collision (co-channel or adjacent channel)
Once you identify any frequency collision, recommend to perform frequency retune. Verify also the frequency hopping technique.

b. Low Signal Strength
This one is based on poor coverage, perform coverage optimization. Adjust antenna tilt or transmit power if necessary.

c. Excessive Timing Advance
Overshooting. TALIM parameters not set properly

d. Others
Transmission Problem - Verify the DIP state of the sites' transmission quality. There could be some "slips" meaning transmission issue.
Congestion on TCH that causes SDCCH to drop - Increase TCH capacity if necessary. Use features such as CLS (Cell Load Sharing) and Dynamic Half Rate allocation.


Hope this helps.

[oucht79]

Dear,
share the results please.
Thx