TS 23.273 – 5G Location Services Architecture Stage 2

1 Scope

The present document specifies the stage 2 of the service-based architecture used for location services in the 5G system, and corresponding Network Functions (NFs), NF services and procedures, to meet the service requirements defined in TS 22.261 [3] and TS 22.071 [2].

Location Services specified in the present document include regulatory location services and commercial location services. The architecture and signalling procedures in NG-RAN are defined in TS 38.305 [9].

4 Architecture Model and Concepts

4.1 General Concepts

A general description of location services and service requirements are given in the specification TS 22.071 [2] and TS 22.261 [3]. Support of location services for GERAN, UTRAN and E-UTRAN access networks is described in TS 23.271 [4], TS 43.059 [5], TS 25.305 [17] and TS 36.305 [7].

The positioning of a UE can be supported by RAT dependent position methods, which rely on for example 3GPP RAT measurements obtained by a target UE and/or on measurements obtained by an Access Network of 3GPP RAT signals transmitted by a target UE. Positioning of a UE can also be supported by RAT independent position methods which may rely on non-RAT measurements obtained by a UE and/or on other information.

The Location Services defined in this specification are applicable to PLMN(s) and within a SNPN as described in clause 6, except for the following features, which are not supported in SNPNs:

- interworking with EPC;

- roaming; and

- direct access to SNPN via non-3GPP access.

The Location Service in PNI-NPN with signalling optimisation is defined as clause 5.13.

The positioning of a UE can be performed by either 3GPP access network or non-3GPP access network. A proper access type shall be determined to assure that the positioning result can fulfil the requested QoS and operator policy.

Location information for one or multiple target UEs may be requested by and reported to an LCS client or an AF within or external to a PLMN or SNPN, or a control plane NF within a PLMN or SNPN. Location information contained in the location request and location information contained in the location response are defined in clause 5.5.

For location request from LCS client (neither in the UE nor in the NG-RAN) or AF external to a PLMN or SNPN, privacy verification of the target UE shall be enabled to check whether it is allowed to acquire the UE location information based on UE LCS privacy profile and whether the LCS client or the AF is authorised to use the location service as defined in clause 5.4. Additionally, UEs may optionally support privacy notification and verification on behalf of a user. Privacy override is also supported for regulatory LCS services according to local regulation.

The capabilities of a target UE to support LCS may be signalled by the UE to a serving PLMN or to an SNPN at the AS, NAS and application (positioning protocol) levels to enable use of position methods supported by the UE.

To provide Location Service in the EPC interworking scenario, an EPC and 5GC common interface shall be used for the location request from LCS client or AF.

Ranging based services and Sidelink Positioning for a UE can be supported, and details are described in clause 5.17.

4.1a Types of Location Request

4.1a.1 Network Induced Location Request (NI-LR)

With a Network Induced Location Request (NI-LR), a serving AMF for a UE initiates localization of the UE for a regulatory service (e.g. an emergency call from the UE) or for verification of a UE location (country or international area) for NR satellite access.

4.1a.2 Mobile Terminated Location Request (MT-LR)

With a Mobile Terminated Location Request (MT-LR), an LCS client or AF external to or internal to a serving PLMN sends a location request to the PLMN (which may be the HPLMN or VPLMN) for the location of a target UE.

4.1a.3 Mobile Originated Location Request (MO-LR)

With a Mobile Originated Location Request (MO-LR), a UE sends a request to a serving PLMN for location related information for the UE.

4.1a.4 Immediate Location Request

With an immediate location request, an LCS client or AF sends or instigates a location request for a target UE (or group of target UEs) and expects to receive a response containing location information…