6 Compatibility issues

3GPP43.073Release 17Stage 2Support of Localised Service Area (SoLSA)TS

LSA can not be used with standard phase 1 or phase 2 mobile stations (or with non-compatible phase 2+ mobile stations) with all service aspects. A dedicated mobile station with LSA capability is required.

A compatible mobile station shall provide the following specific functions:

– cell reselection in case of a LSA subscription;

– notification of the current LSA.

A mobile station with LSA capability shall also provide the complete functionality in order to allow the use of phase 2 services.

Standard phase 1 and phase 2 mobile stations in a network shall not be impacted by the presence of LSA services in that network due to LSA signalling, also if the mobile station is operated with a SIM that contains SoLSA fields.

However, if LSA is provided in a network, it can be applied to non-compatible mobile stations in the following way:

– For a user with a LSA service subscription and with LSA only access, support is given for LSA only access, with exception of the notification (LSA indication).

– For a user with a LSA service subscription, support is given for LSAs in active mode, with exception of the notification (LSA indication).

6.1 Handling of mobiles in exclusive access cells

An escape PLMN may be included for old MSs that do not understand the exclusive access indicator. Such an MS will consider the cell as belonging to another PLMN. If the escape PLMN is broadcast and the subscriber is not allowed within the cell, the receiving MSC/VLR/SGSN shall reject the location update with the cause PLMN not allowed. The escape PLMN will be added to the list of forbidden PLMNs and not accessed again. SoLSA compatible mobile stations will however read the correct PLMN in the system information and treat the cell as normal.