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View Full Version : SDCCH congestion more near railway sites



kb.jayadev
2010-11-12, 06:20 PM
hai,

why SD congetion is high on sectors serving railway lines and how can we reduce it?

electron
2010-11-12, 06:54 PM
hai,

why SD congetion is high on sectors serving railway lines and how can we reduce it?

As a simple solution check SDCCH traffic and utilization on the cell and if required increase SDCCH channel.

tremalnike
2010-11-12, 08:04 PM
When train passing different location area , all passenger phones triggers LA update. That's the main reason.

Solution from electron above + tunning LA borders

Jakkrit
2010-11-13, 02:38 AM
That's right, that site is located on LA border.
Let's me share, I've faced dramatically increase of SD_Blocking on the cell that point out to LA border then I checked alarm for external neighbor and found that the status of neighbor is unstable (it turn off and turn on many times), so it made Ping-pong location update. It causes of increase of SD congestion.

guruvai
2010-11-13, 07:04 AM
hai,

why SD congetion is high on sectors serving railway lines and how can we reduce it?
I want to elaborate tremalnike's comment.

When train passing different location area , all passenger phones triggers LA update. That's the main reason.

Solution from electron above + tunning LA borders

Check those site if they are at LA borders. Then increase the CRH for those.

CRH applies between different LAs. If the CRH value is set too low, the fluctuations in signal strength may lead to a ping-pong effect for location updating. This will cause an undesired increase in the signalling load on the SDCCH. But keep in mind, if the parameter is set too high, the mobile may camp on the wrong cell (not the strongest one) for too long when entering a new location area.