7.2.1 Location Management Procedures

23.1193GPPGateway Location Register (GLR)Release 17Stage 2TS

[Editor’s Note: This clause may be modified after the finalising of restructuring of 3G TS 23.012 [3] and clause 19 of 3G TS 29.002 [10].]

7.2.1.1 Location Updating Procedure

In case of first location updating procedure in the network that introduces the GLR, this procedure is handled by HLR and VLR via GLR. For the second and further location updating, HLR is no longer involved with the procedure. The distinction of those two cases is controlled by GLR so that HLR and VLR is not necessary to be conscious of the difference.

7.2.1.1.1 First Location Updating Procedure

The first location updating procedure in a network is illustrated in figure 7.2/1. Each step is explained in the following list.

Figure 7.2/1: First Location Updating Procedure in the Network

Procedure:

1) When the GLR receives an Update Location message from a VLR and does not hold the subscriber’s information for the user (i.e. at first location updating to the GLR), the GLR:

– stores the VLR Number and serving MSC Number included in the received message, and

– sends an Update Location message to the HLR with the GLR Number as VLR Number, and IM-MSC Number as MSC Number.

2) The HLR stores the GLR Number and IM-MSC Number from received message as respectively VLR Number and serving MSC Number. Thereafter the HLR initiates insert subscriber data procedure and cancel location procedure. When the GLR receives Insert Subscriber Data message from the HLR, the GLR stores the subscriber’s information in the message and transport it to the VLR.

3) After these procedures, the HLR replies to an Update Location message from the GLR and the GLR transports the response to the VLR.

7.2.1.1.2 Second and further Location Updating Procedure

The second and further location updating procedure in the network is illustrated in figure 7.2/2. Each step is explained in the following list.

Figure 7.2/2: Second and further Location Updating Procedure in the Network

Procedure:

1) When the GLR receives an Update Location message from newly visited VLR and holds the subscriber information for the user (i.e. at second or further location updating to the GLR), the GLR stores the new VLR Number and new serving MSC Number included in the received message.

2) Thereafter the GLR initiates insert subscriber data procedure and cancel location procedure.

3) After these procedures, the GLR replies to an Update Location message from the VLR.

7.2.1.1.3 Functional requirements of GLR

7.2.1.1.3.1 Process Update_Location_GLR

Figure 7.2/3 shows SDL chart for Process Update_Location_GLR.

Sheet1: the test "HLR update required?" takes the "yes" exit the GLR checks some flags (ex. CCBS mon. flag) to perform the "Location Updating Screening Function (see to clause 7.1.6)" and if it is needed to update location information to the HLR.

Sheet1: CCBS_Status_Report_GLR procedure is called only if Alternative 2 for CCBS is performed in GLR.

Sheet2: after the GLR sends an Update Location message to the HLR, the GLR receives the response with:

– an Insert Subscriber Data message handled by the procedure Insert_Subscriber_Data_GLR.

– a Forward Check SS indication message. This message will be relayed to the VLR without any change of the current state.

– an Update Location ack message. If the GLR receives this message, this indicates that updating has been successfully completed. The GLR sets the "(Location and Subscriber information) LSIC by HLR" indicator to "Confirmed". The GLR send an Update Location ack message to the VLR.

– an Update Location negative response message. If the GLR receives this message, this indicates that updating has been unsuccessfully completed. The GLR sets the "(Location and Subscriber information) LSIC by HLR" indicator to "False". The GLR sends an Update Location negative to the VLR.

Sheet1: process Cancel_Location_Initiated_GLR is specified in clause 7.2.1.2.1.2.

Sheet5: CCBS_Start_Report_GLR procedure is called only if Alternative 2 for CCBS performed in GLR.

Figure7.2/3(1): Process Update_Location_GLR

Figure7.2/3(2): Process Update_Location_GLR

Figure7.2/3(3): Process Update_Location_GLR

Figure7.2/3(4): Process Update_Location_GLR

Figure7.2/3(5): Process Update_Location_GLR

Figure7.2/3(6): Process Update_Location_GLR

Figure7.2/3(7): Process Update_Location_GLR

7.2.1.1.3.2 Process Subscriber_Present_GLR

Figure 7.2/4 shows SDL chart for Process Subscriber_Present_GLR.

Figure7.2/4: Process Subscriber_Present_GLR

7.2.1.1.3.3 Procedure Insert_Subscriber_Data_GLR

Figure 7.2/5 shows SDL chart for Procedure Insert_Subscriber_Data_GLR. This procedure is initiated by receiving Insert Subscriber Data from the HLR. This procedure is used by Process Update_Location_GLR and Process Update_GPRS_Location_GLR.

Figure7.2/5: Procedure Insert_Subscriber_Data_GLR

7.2.1.1.3.4 Procedure Insert_Subscriber_Data_Initiated_GLR

Figure 7.2/6 shows SDL chart for Procedure Insert_Subscriber_Data_Initiated_GLR. This procedure is initiated if HLR update is not required.

Figure7.2/6(1): Procedure Insert_Subscriber_Data_Initiated_GLR

Figure7.2/6(2): Procedure Insert_Subscriber_Data_Initiated_GLR

7.2.1.2 Cancel Location Procedure

The cancel location procedure in the network when MS leave the network is illustrated in figure 7.2/7. Each step is explained in the following list.

Figure 7.2/7: Cancel Location Procedure in the Network

Procedure:

1) When the HLR receives an Update Location message from newly visited VLR after the MS left the network with the GLR, the HLR initiates cancel location procedure to the GLR.

2) The GLR receives a Cancel Location message from the HLR and transport to the previously visited VLR. When the GLR receives the response, the GLR transports it to the HLR and delete the roamer’s subscriber profile and location information.

3) The HLR initiates insert subscriber data procedure to the newly visited VLR.

4) After the procedure, the HLR returns the response of an Update Location message to the newly visited VLR.

7.2.1.2.1 Functional requirements of GLR

7.2.1.2.1.1 Process Cancel_Location_GLR

Figure 7.2/8 shows SDL chart for Process Cancel_Location_GLR. This process is initiated from the HLR.

Figure7.2/8: Process Cancel_Location_GLR

7.2.1.2.1.2 Process Cancel_Location_Initiated_GLR

Figure 7.2/9 shows SDL chart for Process Cancel_Location_Initiated_GLR. This process is initiated if HLR update is not required.

Figure7.2/9: Process Cancel_Location_Initiated_GLR

7.2.1.3 Handling of unsupported service

The procedure can be used to handle the case where the VLR does not support the full set of services required by the user.

See figure 7.2/10. When the GLR receives the Insert Subscriber Data Acknowledge message indicating "Service Not Supported", it initiates the location updating procedure toward the HLR. The HLR takes some appropriate reaction (e.g. initiates service substitution or roaming restriction etc.) and determines whether to accept the location updating request or not for the user. The HLR generates a new profile (i.e. the profile after service substitution), which must be forwarded by the GLR to the VLR. The GLR must also maintain a copy of the actual service profile for the subscriber (i.e. the profile before service substitution).

The GLR will have to perform some transaction level processing on message 3 (i.e. Insert Subscriber Data ack) from the VLR. Subsequently, when the GLR sends message 6 (i.e. Insert Subscriber Data ack) to the HLR, the message format will have to match that of message 5 (Insert Subscriber Data) from the HLR.

Figure 7.2/10: MS Arrives at a VLR That Cannot Handle all Services

When the user roams from a VLR area with restricted service support into a VLR area where the VLR can support the full set of subscribed services, the GLR must:

– Identify that the new VLR can support the actual service profile required by the HLR, i.e. the profile before service substitution.

– notify the HLR to take the appropriate reaction to restore services. Therefore, the GLR initiates the location updating procedure towards the HLR. (refer to figure 7.2/11 in the case of circuit switched mode).

The GLR will have to perform some transaction level processing on message 3 (i.e. Insert Subscriber Data ack) from the VLR. Subsequently, when the GLR sends message 6 (i.e. Insert Subscriber Data ack) to the HLR, the message format will have to match that of message 5 (Insert Subscriber Data) from the HLR.

Figure 7.2/11: MS Arrives at a VLR That Handles all Services