Cisco Cisco ASR 5000
Location Services
How Location Services Works ▀
SGSN Administration Guide, StarOS Release 18 ▄
How Location Services Works
The SGSN LCS responsibilities center around UE subscription authorization and managing LCS positioning requests.
The LCS functions of the SGSN are related to charging and billing, LCS co-ordination, location request, authorization
and operation of the LCS services.
The LCS functions of the SGSN are related to charging and billing, LCS co-ordination, location request, authorization
and operation of the LCS services.
When using the Iu interface, before the SGSN can request location information of a target UE from the radio access
network (RAN), an Iu signaling connection must have been established between the SGSN and the RAN. The SGSN
sends a Location Request message to the RAN. The RAN determines the location of the target UE related to this Iu
signaling connection and sends a Location Report to the SGSN over the same Iu signaling connection. On the Iu
interface, only one location request for a geographic location estimate can be ongoing at any time.
network (RAN), an Iu signaling connection must have been established between the SGSN and the RAN. The SGSN
sends a Location Request message to the RAN. The RAN determines the location of the target UE related to this Iu
signaling connection and sends a Location Report to the SGSN over the same Iu signaling connection. On the Iu
interface, only one location request for a geographic location estimate can be ongoing at any time.
Only one location request can be ongoing at any time.
The operation begins with a LCS Client requesting location information for a UE from the LCS server. The LCS server
will pass the request to the LCS functional entity (SGSN) in the core network. The LCS functional entitiy (SGSN) in the
core network then:
will pass the request to the LCS functional entity (SGSN) in the core network. The LCS functional entitiy (SGSN) in the
core network then:
1. verifies that the LCS Client is authorized to request the location of the UE or subscriber;
2. verifies that location services are supported by the UE;
3. establishes whether it (the MME/SGSN) is allowed to locate the UE or subscriber, for privacy or other reasons;
4. establishes which network element in the radio access network ( GERAN or UTRAN or E-UTRAN ) should
2. verifies that location services are supported by the UE;
3. establishes whether it (the MME/SGSN) is allowed to locate the UE or subscriber, for privacy or other reasons;
4. establishes which network element in the radio access network ( GERAN or UTRAN or E-UTRAN ) should
receive the Location Request;
5. requests the access network (via the A, Gb, Iu or S1 interface) to provide location information for an identified
UE, with indicated QoS;
6. receives information about the location of the UE from the Access Network and forward it to the Client;
7. sends appropriate accounting information to an accounting function.
7. sends appropriate accounting information to an accounting function.
Relationship to Other SGSN Functions
The Location Services feature utilizes several of the existing SGSN functionalities:
Mobility Management module
MAP Service module
Architecture
The MME is accessible to the Gateway Mobile Location Center (GMLC) via the SLg interface.
The SGSN is accessible to the GMLC via the Lg interface.