Downlink Power congestion problem

**scatter** · 2012-01-05, 04:18 AM

Hi,

We have a problem with RRC rejects due to DL power in few sites. This happens during normal as well as peak traffic hours.
The power usage is 40% to 50% with lot of PS and few CS users and suddenly the power usage spikes to 90% leading to RRC rejects.

Node : E******* RNC 3820/ RBS 6000

I have checked the maximumTransmissionPower and primarcyCpichPower settings. They are like any other normal cells with out having this problem.

I have seen from the DL common power measurements from RBS the phenomenon of sudden surge in the power usage.

How to go about this problem ?

Any suggestions will be appreciated.

Best Regards
V

**Finetopix** · 2012-01-05 04:18 AM

**rishi** · 2012-01-05, 04:17 PM

did you check IUB congestion and usage of CE for those sites.

what doe it say??

**Philippe** · 2012-01-05, 05:36 PM

Is HSDPA activated on those sites?

**scatter** · 2012-01-05, 06:01 PM

For instance, exactly after 1 second after the below data was taken, the Non HS TX power shoots above 90%

dl-non-hs-tx-power

ase-ul

ase-dl

code-tree-consumption

sf8dl

sf16dl

sf32dl

cm-users

hs-users

sf4ul

sf8ul

sf16ul

62

58.35

25.06

33

0

1

17

1

0

4

IUB congestion - Should i check form some utrancell counters for this ?

Thanks

Originally Posted by rishi

did you check IUB congestion and usage of CE for those sites.

what doe it say??

**scatter** · 2012-01-05, 06:02 PM

Yes Philippe, HSDPA is activated on the sites. I am talking about the DL Non-HS transmit power.

Originally Posted by Philippe

Is HSDPA activated on those sites?

**fon909** · 2012-01-05, 06:55 PM

Please check the following;

1. Power Utilization trend
2. CS/PS traffic trend
3. Cell is overshooting
4. Physical modification on the site (tilt etc)
5. Number of HSDPA and Eul users
6. Alarms / Hw (needless to say, am sure you must have checked)

Please also check if any of the following power parameters were modified;

1. pwrAdm
2. pwrAdmOffset
3. pwrOffset
4. pwrHyst

Please prepare a proper RNC wise/ Cell wise - Daily / hourly trend, will help you pin-point cells and identify hours where the problem is observed. Identify the day since this problem started, compare the parameter dump before and after for any inconsistencies.

Thanks. Hope this helps.
If you identify the real problem then please share, will help enhance our knowledge.

**epaange** · 2012-01-05, 09:46 PM

Check the RRC load !

**electron** · 2012-01-05, 10:15 PM

Hi friend,

The problem is your maximumtotaloutputpower is limited for the RBS. Firstly connect to the RBS and check this parameter value via moshell(AMOS) by command "get . maxtot" it should be 60 which means your RUW is propagating 60W but if it is -1 means it is propagating 30W and because of that you have lack of power and will face admition triggered be careful exactly after change make a startable CV.

PS: Check licnese in RBS does it installed? if it was in emergency unlocked mode and if now it expired now you can not change the mentioned parameter to 60

Give feedback please for further guidance

**Aljunaibi** · 2012-01-08, 08:08 PM

If it's power congestion then you have the below actions to try:-

- Reduce PCPICH power
- Down tilt
- Add extra RRU and introduce new carrier over it.

**scatter** · 2012-01-09, 09:17 PM

Hi All,

thanks for the suggestions so far.

all the sites that have these dl power problem are located near or very near to the train station.

We also observed that DL PWR spike coincides with the increase in the usage of DL SF. So its potentiall R99 PS users who are responsible for the problem.

Planning to restric the below SF codes in the cell and observe the Power problem.

sf16Adm
sf32Adm
sf8Adm

Any feedback will be appreciated.

Regards
V