Roaming Issue : 3G Ue camping forever on VPLMN

[elkador]

Hi Experts,

Some background info : we are speaking UMTS/HSPA network here.

Anybody could bring me light on this issue :
- We have a roaming agreement with another operator (not seamless, our UE have to get out of our coverage, drop, and then register on the VPLMN).
- We set the T3212 to minimal value (6 minutes) in order to get our customers back as soon as we can.
- Problem : we are seing UEs in idle mode still camping for a very long time on the VPLMN (more than 20mins) instead of going back on the HPLMN...

Any hints to share?
Could it be UE dependant? Is there any specific parameter that could explain such a behaviour?

Thanks for your help!

[kamy]

Hi Experts,

Some background info : we are speaking UMTS/HSPA network here.

Anybody could bring me light on this issue :
- We have a roaming agreement with another operator (not seamless, our UE have to get out of our coverage, drop, and then register on the VPLMN).
- We set the T3212 to minimal value (6 minutes) in order to get our customers back as soon as we can.
- Problem : we are seing UEs in idle mode still camping for a very long time on the VPLMN (more than 20mins) instead of going back on the HPLMN...

Any hints to share?
Could it be UE dependant? Is there any specific parameter that could explain such a behaviour?

Thanks for your help!

the fact that, you can not decide for both sides instead of the other

[elkador]

the fact that, you can not decide for both sides instead of the other

You mean that the Roaming Operator could set a different value for the T3212 timer, and then the UE would use this value to try to register back on our network?

[kamy]

You mean that the Roaming Operator could set a different value for the T3212 timer, and then the UE would use this value to try to register back on our network?

when you are being in someone house, you are controlled by the owner. My network is as the same yours

[elkador]

when you are being in someone house, you are controlled by the owner. My network is as the same yours

So I guess the only way to quickly move our UEs back on our network would be to ask the Roaming Operator to disable roaming on selected sites (typically where our respective coverage overlaps)... Thanks anyway for your input, it's really appreciated!

[s52d]

Wow, T3212 on 6 minutes, you really have empty network and happy phone charging users.
Any complains like: my batteries are gone much faster in this network compared to VPLMN?


T3212 is just "guard" parameter: if terminal is destroyed, battery removed etc, take it out of VLR.
When judging benefit of accurate VLR dB (paging success) versus signalling load/battery consumption we decided to keep it on 12 hours: some terminals just never do periodic
location area updates here.
When we suspect VLR corruption, T3212 is set to 30 minutes for a while.


Now, in real roaming, the only trigger to do PLMN reselection is loss of serving PLMN signal.
For national roaming, you can enable SIM card parameter named like HOMEPLMNSEARCH or simmilar - it tells terminals how often they should saearch for your network while camping
on another network with same MCC-MNC.

We did some tests years ago, and some terminals simply ignored this settings.

BR
s52d

Hi Experts,

Some background info : we are speaking UMTS/HSPA network here.

Anybody could bring me light on this issue :
- We have a roaming agreement with another operator (not seamless, our UE have to get out of our coverage, drop, and then register on the VPLMN).
- We set the T3212 to minimal value (6 minutes) in order to get our customers back as soon as we can.
- Problem : we are seing UEs in idle mode still camping for a very long time on the VPLMN (more than 20mins) instead of going back on the HPLMN...

Any hints to share?
Could it be UE dependant? Is there any specific parameter that could explain such a behaviour?

Thanks for your help!

[elkador]

Wow, T3212 on 6 minutes, you really have empty network and happy phone charging users.
Any complains like: my batteries are gone much faster in this network compared to VPLMN?


T3212 is just "guard" parameter: if terminal is destroyed, battery removed etc, take it out of VLR.
When judging benefit of accurate VLR dB (paging success) versus signalling load/battery consumption we decided to keep it on 12 hours: some terminals just never do periodic
location area updates here.
When we suspect VLR corruption, T3212 is set to 30 minutes for a while.


Now, in real roaming, the only trigger to do PLMN reselection is loss of serving PLMN signal.
For national roaming, you can enable SIM card parameter named like HOMEPLMNSEARCH or simmilar - it tells terminals how often they should saearch for your network while camping
on another network with same MCC-MNC.

We did some tests years ago, and some terminals simply ignored this settings.

BR
s52d

Yup. totally agree on the battery issue. Since we are not officially commercial we can still pay this price.

Concerning the HOMEPLMNSEARCH setting : indeed it seems we have different behaviour depending of the UE (especially USB Aircard), so I was wondering if we could use an alternative way...

[s52d]

Once again:
- T3212 is unrelated to moving of terminals
- it is SIM card parameter, on top of terminal.

Not being commercial: Wellcome to the club! It is allways fun to build new network!

Yup. totally agree on the battery issue. Since we are not officially commercial we can still pay this price.

Concerning the HOMEPLMNSEARCH setting : indeed it seems we have different behaviour depending of the UE (especially USB Aircard), so I was wondering if we could use an alternative way...

[wolverine]

s52d is right, you should use the homePLMN timer on the SIM/USIM card to control when the handset scans for the HPLMN not T3212. If some handsets are not obeying this timer you should raise it as a defect with the supplier via your terminals dept.

[elkador]

Just to keep you informed : the HPLMNSP is currently set to 6 min.
But we are still seing strange behaviour from the UEs...
Could it be something like :
UE would better stick to the GSM roaming network instead of going to 3G HPLMN when the HPLMNSP expires?