4.3.8 Service registration and location update

23.1213GPPArchitectural requirements for Release 1999Release 1999TS

Service registration (attach) in the respective CN service domain is done initially (after UE being detached due to e.g. power off). When a registration area is changed a location update is performed. In addition, periodic registration can be performed. Here follows descriptions of when the respective CN registration area is changed.

NOTE: It is not here defined which different registration procedures that are needed.

4.3.8.1 Location area update

Location area update is initiated by the UE to inform the CS service domain of the core network that the UE has entered a new location area. In case the new location area is in an area served by another CN node, the location area update also triggers the registration of the subscriber in the new CN node and a location update for CS services towards the HLR.

Location area update is only initiated by the UE when the UE is in state CS-IDLE, and this independently of the PS state. If the UE is CS-IDLE but RRC connected, which means that the UE is in PS-CONNECTED state, location area update is initiated by the UE when it receives information indicating a new location area (see also the chapter "Handling of MM system information").

4.3.8.2 Routing area update

Routing area update is initiated by the UE to inform the PS service domain of the core network that the UE has entered a new routing area. In case the new routing area is in an area served by another CN node, the routing area update also triggers the registration of the subscriber in the new CN node and a location update for PS services towards the HLR.

Routing area update is initiated by the UE when the UE is in state PS-IDLE, and this independently of the CS state. If the UE is PS-IDLE but RRC connected, which means that the UE is in CS-CONNECTED state, routing area update is initiated by the UE when it receives information indicating a new routing area (see also the chapter "Handling of MM system information").

When the UE is in PS-CONNECTED state the UE initiates RA update when RAI in MM system information changes.

4.3.8.3 Combined updates

The GSM radio interface combined procedures and their support via the Gs interface is the starting point for the support of combined updates.