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Penalty Time -> 2G to 3G

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pix - 23rd April 2014  (10:46 GMT)


which status the UE will be after IRAT PS handover from3g to 2g?

The MS in 2G will be in PTM, after a 3G2G IRAT PS reselection.

If you want to make the reselection to 3G more difficult during 2G PTM, then increase FDD_GPRS_Qoffset.


Styrax - 23rd April 2014  (09:25 GMT)

Hi Pix,

Just to clarify that, below you cited different 2G ALU parameters for 2g-3g reselection, what I'm trying to do is to make the reselection from 2g to 3g difficult and that by changing the "FDD_Qoffset" and "FDD_GPRS_Qoffset" value.
But i am confused, which one of previous parameters should i change? the 1srt is for MS in idle mode and the 2nd is for MS in PTM (transfer mode), that's why i asked you previously in which status the UE will be after IRAT PS handover from3g to 2g?

PLZ clarify this point
Many thx

pix - 22nd April 2014  (18:30 GMT)


the UE can come from 3G to 2G in idle mode, in speech dedicated mode or/and in packet dedicated mode.

All scenarios are possible, and might be independantly activated or deqctivated.

If you have an issue of idle pingpong between 3G and 2G, then you must ensure that idle "exit parameters" from 3G have weaker values than the idle "exit parameters" from 2G.

You have to put both idle algo side by side in order to find a stable stragegy.


Tyrax - 22nd April 2014  (16:31 GMT)

Hi Pix,

PLZ the UE come from 3g to 2g, it will be in which status? idle, PIM or PTM?
because i'm facing same Pb as "Optim", so do you have an idea how to avoid the UE reselection back to 3g when he came from 3G cell?


pix - 25th January 2011  (19:46 GMT)


I think those parameters are generic, because reselection is a very generic (3GPP) procedure. If there are some differences, I'm certain they are minimal and will be easily overcome by a tenacious mind.

Only the HO 2G to 3G is not standard (i think) so I'll let you handle that one by yourself.

Let me know how it goes,


Optim - 25th January 2011  (13:11 GMT)

Thanks Loads Pix !!

But I also forgot to mention that our equipment is Ericsson . . .

Any idea abt their parameters or the ones quotes by you are generic?

many Thanks

pix - 25th January 2011  (13:00 GMT)

and I forgot something : are you using NC2 or not, in GPRS PTM ?

pix - 25th January 2011  (13:00 GMT)


here are the most important parameters... and my recommendations. Feel free to challenge them, or to discuss them, because I can't be certain those will work in your particular network.

EN_2G_TO_3G_CELL_RESELECTION = 1: Enabled with 3G search activated while the UE/MS is in GMM ready state
* to allow the 3G reselection *

* to reduce signalling load *

EN_CPICH_2G_3G_RESELECTION = 1: CPICH Ec/No and RSCP measurements must be used
* to ensure both level and C/I of the 3G are good *

EN_FAST_3G_RESELECTION = 1:only fast 3G cell reselection at 2G CS call release is used.
* up to you, use it (1) or don't (0) *

FDD_GPRS_Qoffset = 10dB
* when the MS is in GPRS PTM, it can reselect 3G cells which are 10dB better than 2G serving cell only. With such setting, the 3G reselection must be very difficult * * default = -32dB*

FDD_Qoffset = -10dB
* when the MS is in idle mode, it can reselect 3G cells with level(3G) > level(2G) - 10dB. With such setting, the 3G reselection must be more difficult than before * * default = -32dB*

FDD_Qmin = -6dB
FDD_Qmin_Offset = -4dB
* reselection only to 3G cells where Ec/No > -6dB (for pre R5 MS) or where Ec/No > -10dB (for post R5 MS) * (default = -12dB for all MS)

FDD_RSCPmin = -95dBm
* reselection only to 3G cells with RSCP > -95dBm * (default = -102dBm)

Qsearch_I (Idle mode / not GPRS attached) = Always (value 7)
Qsearch_P (GPRS PIM) = Always (value 7)
Qsearch_P_PTM (GPRS PTM) = Always (value 7)

* when would the MS start looking for 3G cells... this is very special, I'll let you look it up by yourself.. I recommend the value "always" in your case, to avoid a roblem. But you can optimize this value. When the MS stops looking for 3G cell, it saves battery !! So you could for example force the MS to search for 3G cell only when the 2G level is less than -74dBm (value 6), or only when the 2G level is better than -70dBm (value 10. It so strongly depends on your network design that I can't recommend anything else than "always" :) *

Enjoy :) (these are very precious advices, for customers...)


Optim - 25th January 2011  (12:14 GMT)

Hi Xperts and Pix,

I need to know about some Penalty time that we want to apply on certain Connections when they come from 3G to 2G . . . so that they don't go back to 3G instantly.



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