E// Discarded Paging Counters PAGETOOOLD, how long will stay before being discarded??

[khaldounh]

Hi Experts

How long ( time ) the paging request will stay in the queue of the paging group before being discarded so I can correlate it with the time of MSC re-transmission timier.


Br

Khaldoun

[babak1349]

Hi mate,
Regarding to your questions there are 2 items you should consider:
1) how RNC handles received paging messages from core Network
2) How Core network sends the paging message to Radio part

In RNC the paging is repeated NoOfPagingRecordTransm times NO matter if the first paging was successful
Each paging message will be send over DRX cycle and Drx cycle time is defined by (10 * Pow (2,cnDrxCycleLengthCs)) If for example the cnDrxCycleLengthCs is 6, it means DRX Cycle is 640 ms
so RNC repeat the received paging message NoOfPagingRecordTransm times and it takes NoOfPagingRecordTransm *640 Ms to complete the messages
There is a point here if RNC CAN NOT allocate PICH during a DRX cycle (for example due to congestion on PICH ) it tries for the other DRX cycle till succeeds or maximum number allowed DRX reaches with is 5120 ms so sending the each paging message may varies in Radio access part So as in the example the paging duration is Not 1280 ms and it may not be rejected after that duration RNC may discard the Paging message due long queuing (cause it can not allocate the PICH)
So if you see high discared or rejected paging message it could be due to congestion on PICH and you need to fix it

In MSC if there is active IMSI in VLR, MSC pages first the TMSI and if no success it pages globally the IMSI and then it may sends the 2nd paging I think the default values for paging a user in MSC is more than 10 seconds which is really long to page a user while in Radio side a page may discarded after maximum 10 sec.

So mainly you need t othink about potential congestion over Radio interface ( and also CC device load as it is responsible for paging in RNC)
You need to look at the PICH load generated from CS and PS domain separately ( now days it mainly generated by PS core) and calculate the paging intensity in whole RNC and paging intensity generated by CS/PS domain separately and you need to modify paging parameters in SGSN or even think about dividing RA (routing areas)

You can check RA and LA planning guidelines in Alex lib for more details


Cheers





Hi Experts

How long ( time ) the paging request will stay in the queue of the paging group before being discarded so I can correlate it with the time of MSC re-transmission timier.


Br

Khaldoun

[alibushehri]

Hi,

It's 5 seconds and also it's hard coded which means you cannot change it.

Ali B



Hi Experts

How long ( time ) the paging request will stay in the queue of the paging group before being discarded so I can correlate it with the time of MSC re-transmission timier.


Br

Khaldoun

[khaldounh]

Thank you very much mates.

@alibushehri (http://www.finetopix.com/member.php?3082-alibushehri)
Sorry to say that, but how did you know, where can I get this (and such) info.

@babak1349 (http://www.finetopix.com/member.php?24711-babak1349)
Thank you too sir ;)



Thanks

[babak1349]

Hi Mate,
Sorry my description was for 3G and your question is about 2G
I'd like to highlight some points:
in BSC/RNC , they are responsible to send the Paging messages successfully on air interface and they are not responsible for successful paging procedure (Core side is responsible) So in Radio part, paging success rate means successfully sending pag message and it does not count the paging response
So in GSM due to congestion on air interface (PCH on CCCH) the paging meesage can stay in the queue and when ever BSC picks up am paging message from the queue it compares the age of paging message with a parameter which is named "AGE-OF-PAGING" and if it is older, the paging message will be discarded "AGE-OF-PAGING" is the parameter you are looking and it seems it is hardcoded and set to 5 s Or it could be a hidden parameter (it means E******* keeps it for E******* engineer to change it and normally operator from normal extracting dumps can not see it)
Again The discard PageTooold can happen due to congestion on Air interface it means you don't have enough PCH blocks so you may change 2 parameters AGBLK or MFRMS to make more paging block per signaling frame or increasing paging group

Here is a document which may help you
http://www.scribd.com/doc/123150087/Analysis-and-Optimization-of-Paging-Success-Rate-ppt

Cheers


Thank you very much mates.

@alibushehri (http://www.finetopix.com/member.php?3082-alibushehri)
Sorry to say that, but how did you know, where can I get this (and such) info.

@babak1349 (http://www.finetopix.com/member.php?24711-babak1349)
Thank you too sir ;)



Thanks

[khaldounh]

Interesting really really interesting, appreciated bro

Cheers