Reselection Parameter from 3G to 2G

[kema2103]

Hi,

I have question about the following parameter setting which could be a problem. The parameter “SSearchRAT“ is decreased from the value 4 dB to 2dB. The Ue starts the 2G measurements when the Eke/No are -16dB.

In my opinion, it makes no sense to have this setting, because calls which belong to 2G should be reselected to 2G and not longer stay in 3G.

Could you prove that for me? Any hint, comment is appreciated.

[tsiz]

Hi,

I have question about the following parameter setting which could be a problem. The parameter “SSearchRAT“ is decreased from the value 4 dB to 2dB. The Ue starts the 2G measurements when the Eke/No are -16dB.

In my opinion, it makes no sense to have this setting, because calls which belong to 2G should be reselected to 2G and not longer stay in 3G.

Could you prove that for me? Any hint, comment is appreciated.


sRatSearch is the parameter used when GSM frequencies should be measured.

so when Squal>sRatsearch, Ue will not perform GSM measurements but,

when Squal<sRatsearch, Ue starts measuring GSM cells.

Where Squal is defined as qQaulmeasured-qQualmin>0

So only if if reaches this criteria will GSM be measured.

What is your qQualmin set to? Is it -20 or lower?

[jan74]

Hi,

I have question about the following parameter setting which could be a problem. The parameter “SSearchRAT“ is decreased from the value 4 dB to 2dB. The Ue starts the 2G measurements when the Eke/No are -16dB.

In my opinion, it makes no sense to have this setting, because calls which belong to 2G should be reselected to 2G and not longer stay in 3G.

Could you prove that for me? Any hint, comment is appreciated.

Not sure what you are trying to do here. If you have SsearchRAT=2dB and QqualMin= -18dB, then your InterRAT search in idle mode will begin at Ec/No=-16dB. If you are saying that you have reduced it from 4dB to 2dB, then the mobile will stay on 3G a bit longer, avoiding the InterRAT search procedure. There are some reasons to do this:

1. If you do not own the GSM network and it is costing you roaming fees to reselect GSM, you may want to reduce the number of users going to GSM

2. If your GSM network is stuck for capacity.

3. If you want to reduce the number of users getting stuck on GSM when they have Smartphones. This is a good idea if you have iphone 4 in your network because the Inter RAT scan will only happen every 6 minutes and cannot be changed. The result is customers stuck on GPRS or some other slow GSM data service. It is very frustrating.

Please clarify what exactly you need to know

[kema2103]

Hi,

qQualmin set to to -18,

aim is to avoid ping-pong in the network between 3G and 2G, where in case that 3G has poor coverage is to keep customer under 2G, so MO is owner of both frequencies and there is no problem with 2G capacity at all, so just try to avoid ping pong effect where becuase of timing in reselection from 3G to 2G and then backwards call drops could occur, so what you are advicing in this case?

thanks again.

[jan74]

Hi,

qQualmin set to to -18,

aim is to avoid ping-pong in the network between 3G and 2G, where in case that 3G has poor coverage is to keep customer under 2G, so MO is owner of both frequencies and there is no problem with 2G capacity at all, so just try to avoid ping pong effect where becuase of timing in reselection from 3G to 2G and then backwards call drops could occur, so what you are advicing in this case?

thanks again.

What settings have you got for the reselection from 2G to 3G? If you dont care about the user being on 2G, then you should look at changing the SsearchRAT back from 2dB to 4dB. That way, you will leave 3G earlier(at -14dB) and will camp on 2G if available. To avoid coming straight back, you need then to set your 2G levels at high level.

[kema2103]

Thanks Jan,

I will check for settings from 2G to 3G and I will verify your advice,

thanks again.

[jan74]

Thanks Jan,

I will check for settings from 2G to 3G and I will verify your advice,

thanks again.

No problem. Its fairly straightforward really as you just want to increase the buffer between 3G to 2G and 2G to 3G. However, it might be a good idea to look again at the strategy as a whole in light of the amount of smartphones out there. There is nothing worse than getting stuck on 2G data. Presumably you have enabled ISHO from 2G to 3G in the case the user requests data on 2G and 3G is available?

[wolverine]

@jan74

what do you mean by "This is a good idea if you have iphone 4 in your network because the Inter RAT scan will only happen every 6 minutes and cannot be changed. The result is customers stuck on GPRS or some other slow GSM data service. It is very frustrating."

I have never heard of iphone4 scanning every 6 min. Where did you get this info from?

[adewijaya]

@jan74

what do you mean by "This is a good idea if you have iphone 4 in your network because the Inter RAT scan will only happen every 6 minutes and cannot be changed. The result is customers stuck on GPRS or some other slow GSM data service. It is very frustrating."

I have never heard of iphone4 scanning every 6 min. Where did you get this info from?

better using factual of data more be appreciated, frequently scanning will be loaded signalling then it will be suffering whole network

[jan74]

@jan74

what do you mean by "This is a good idea if you have iphone 4 in your network because the Inter RAT scan will only happen every 6 minutes and cannot be changed. The result is customers stuck on GPRS or some other slow GSM data service. It is very frustrating."

I have never heard of iphone4 scanning every 6 min. Where did you get this info from?

I know for sure as i have tested it.... We noticed the iphone 4 stays on GSM a lot longer than every other UE aprt from the iphone 3GS. Check your stats and you will find the same. The issue , apart from the inferior antenna, is that the normal Network Scan when not on the Home PLMN should happen after 2 minutes, and then every 6minutes. However, the iphone 4 skips the 2min scan and only does every 6. At least in NSN, this cannot be changed.

[sugunthan]

Hi,

I am still new here.
Can anyone help ?

May I know wat's the reason when 2G to 3G reselection taking too much of time?

Thanks.

-/sugu

[Interface]

Base on my experience, this action may be useful in one of some cases as below:
- Keep the MS at 3G more time --> Reduce the capacity at GSM cosite.
- Reduce ping pong problem --> Increase the PSR because when UE start cell reselection 2G-3G, UE can't listen the paging.