TEMS wierd behaviour

[Mdaf]

Hello,
I have noticed the following scenario on different TEMS handsets at different network locations.
When you enter and area with pilot polution the TEMS goes to other operators 3G!! Keeping in mind tht 2G ngbrs are defind and have coverage im that area, what makes the TEMS do that?
many thanks

[TIGRI007]

Even I faced that problem. But mostly in the country borders (even with sim card Roaming disabled)

[tremalnike]

Some phones has the same behavior - it's not related to TEMS

[TIGRI007]

Is there any parameter to change from network to avoid this problem?

[Mdaf]

Some phones has the same behavior - it's not related to TEMS
Intresting but do you know why?

[tremalnike]

Actually I don't know. I suppose that this is related to cell selection algorithms used by chipsed vendor/manufacturer, because after coverage lost, UE performs initial cell selection.

[xsdenied07]

PLMN selection and roaming

The MS normally operates on its home PLMN (HPLMN). However a visited PLMN (VPLMN) may be selected, e.g., if the MS loses coverage. There are two modes for PLMN selection:
i) Automatic mode - This mode utilizes a list of PLMNs in priority order. The highest priority PLMN which is
available and allowable is selected.
ii) Manual mode - Here the MS indicates to the user which PLMNs are available. Only when the user makes a
manual selection does the MS try to obtain normal service on the VPLMN.
There are two cases:
- International Roaming - This is where the MS receives service on a PLMN of a different country than that of the HPLMN.
- National Roaming - This is where the MS receives service from a PLMN of the same country as that of the HPLMN, either anywhere or on a regional basis. The MS makes a periodic search for the HPLMN while national roaming.
To prevent repeated attempts to have roaming service on a not allowed LA, when the MS is informed that an LA is forbidden, the LA is added to a list of "forbidden LAs for roaming" which is stored in the MS. This list is deleted when the MS is switched off or when the SIM is removed. Such area restrictions are always valid for complete location areas independent of possible subdivision into GPRS routing areas. The structure of the routing area identifier
supports area restriction on LA basis. If a "PLMN not allowed" message is received by an MS in response to an LR request from a VPLMN, that VPLMN is
added to a list of "forbidden PLMNs" in the SIM and thereafter that VPLMN will not be accessed by the MS when in automatic mode. A PLMN is removed from the "forbidden" list if, after a subsequent manual selection of that PLMN, there is a successful LR. This list is retained when the MS is switched off or the SIM is removed. The HPLMN shall not be stored on the list of "forbidden PLMNs".

A ME not supporting SoLSA may consider a cell with the escape PLMN code to be a part of a PLMN belonging to the list of "forbidden PLMNs".Optionally the ME may store in its memory an extension of the forbidden PLMN list. The contents of the extension of the list shall be deleted when the MS is switched off or the SIM is removed