5.3.9 HSS User Profile management function procedure

23.4013GPPGeneral Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) accessRelease 18TS

5.3.9.1 General

The HSS user profile management function allows the HSS to update the HSS user profile stored in the MME. Whenever the HSS user profile is changed for a user in the HSS, and the changes affect the HSS user profile stored in the MME, the MME shall be informed about these changes by the means of the following procedure:

– Insert Subscriber Data procedure, used to add or modify the HSS user profile in the MME.

5.3.9.2 Insert Subscriber Data procedure

The Insert Subscriber Data procedure is illustrated in Figure 5.3.9.2-1.

Figure 5.3.9.2-1: Insert Subscriber Data procedure

1. The HSS sends an Insert Subscriber Data (IMSI, Subscription Data) message to the MME.

2. The MME updates the stored Subscription Data and acknowledges the Insert Subscriber Data message by returning an Insert Subscriber Data Ack (IMSI) message to the HSS. The update result should be contained in the Ack message.

The MME initiates appropriate action according to the changed subscriber data (e.g. MME initiates detach if the UE is not allowed to roam in this network). For received PDN subscription contexts that have no related active PDN connection in the MME, no further action is required except storage in the MME. Otherwise if the subscribed QoS Profile has been modified and the UE is in ECM‑CONNECTED state or in ECM-IDLE state when ISR is not activated but the UE is reachable by the MME, the HSS Initiated Subscribed QoS Modification procedure, as described in Figure 5.4.2.2-1, is invoked from step 2a. When ISR is not activated and the UE is in ECM IDLE state and is not reachable by the MME, e.g. when the UE is suspended, when the UE has entered into power saving mode or when the PPF is cleared in the MME, the HSS Initiated Subscribed QoS Modification procedure, as described in Figure 5.4.2.2-1, is invoked from step 2a at the next ECM IDLE to ECM CONNECTED transition. If the UE is in ECM‑IDLE state and the ISR is activated, this procedure is invoked at the next ECM‑IDLE to ECM‑CONNECTED transition. If the UE is in ECM‑IDLE state and the ISR is not activated and if the subscription change no longer allows the PDN connection, the MME initiated PDN disconnection procedure in clause 5.10.3 is used to delete the concerned PDN connection. If the MME receives RAT specific Subscribed Paging Time Window that is different from the one stored in the MME MM context, the MME updates RAT specific Subscribed Paging Time Window parameter in the MME MM context to the value received from the HSS.

If the UE is in ECM-CONNECTED state and connected via a CSG or hybrid cell, the MME shall check the received CSG subscription data. If the MME detects that the CSG membership to that cell has changed or expired, the MME initiates the procedure in clause 5.16.

If the MME received a changed Service Gap Time parameter in the updated subscription data, the MME shall provide the new Service Gap Time value to the UE in the next Tracking Area Update Accept message, or, if the UE does not send any Tracking Area Update Request within a certain time period that shall be longer than any PSM or eDRX interval used by the UE, the MME may initiate a detach with reattach required of the UE or an RRC connection release with release cause load balancing TAU required of the UE.

5.3.9.3 Purge function

The Purge function allows an MME to inform the HSS that it has deleted the subscription data and MM context of a detached UE. The MME may, as an implementation option, delete the subscription data and MM context of an UE immediately after the implicit or explicit detach of the UE. Alternatively the MME may keep for some time the subscription data and the MM context of the detached UE, so that the data can be reused at a later attach without accessing the HSS.

Figure 5.3.9.3-1: Purge Procedure

1. After deleting the Subscription data and MM contexts of a detached UE, the MME sends Purge UE (IMSI) message to the HSS.

2. The HSS sets the UE Purged for E-UTRAN flag and acknowledges with a Purge UE Ack message.