Description
Network Induced Location Request (NI-LR) is a core network-driven procedure within the 3GPP Location Services (LCS) architecture. It enables an authorized entity, known as a LCS Client, to request the geographical position of a target UE. The key characteristic of NI-LR is that the location request is triggered by the network or an external application server, not by the UE (which would be a Mobile Originated Location Request, MO-LR). The requesting LCS Client can reside within the network operator's domain (e.g., for emergency services, lawful interception) or be an external, trusted third-party service provider (e.g., for logistics or asset tracking). The request is submitted to the Gateway Mobile Location Centre (GMLC), which acts as the gateway and privacy authorizer for all location requests.
Upon receiving a validated NI-LR, the GMLC routes the request to the appropriate serving node in the core network—the Mobile Switching Centre (MSC) for circuit-switched (CS) access, the Serving GPRS Support Node (SGSN) for 2G/3G packet-switched (PS) access, or the Mobility Management Entity (MME) for 4G/5G access. This serving node then initiates the positioning procedure with the target UE and the radio access network (RAN). The specific positioning method (e.g., Cell-ID, OTDOA, UTDOA, A-GNSS) is determined by the network based on the required Quality of Service (QoS) such as accuracy and response time. The RAN and/or UE perform the necessary measurements (e.g., timing measurements for OTDOA, satellite signals for A-GNSS) and report them to a dedicated network node, the Enhanced Serving Mobile Location Centre (E-SMLC) in LTE or the Location Management Function (LMF) in 5G. This node calculates the final position estimate.
The calculated location estimate is then routed back through the chain: from the E-SMLC/LMF to the serving node (MME/SGSN/MSC), then to the GMLC, and finally delivered to the requesting LCS Client. Throughout this process, privacy is paramount. The network must verify that the LCS Client is authorized for the specific type of request and that the target subscriber's privacy settings, stored in the Home Subscriber Server (HSS) or Home Location Register (HLR), permit such a network-induced location disclosure. The NI-LR procedure is therefore a complex orchestration of authorization, signaling, radio measurement, and calculation across multiple network entities.
Purpose & Motivation
NI-LR was developed to meet critical regulatory, safety, and commercial needs that require the network to be able to locate a subscriber without their active participation. The most significant driver was regulatory mandates for emergency caller location. When a user makes an emergency call (e.g., 112, 911), the network must automatically determine the caller's location to dispatch aid, even if the caller is unable to provide it or is unaware of their position. NI-LR provides the standardized mechanism for this automatic network-triggered location.
Beyond emergencies, NI-LR addresses requirements for lawful interception and location-based services. Law enforcement agencies, with proper legal authorization, require the capability to locate a subscriber for security purposes. Commercially, it enables a wide range of value-added services. For example, a logistics company can track its fleet vehicles, a network operator can implement location-dependent charging (e.g., different rates at home vs. abroad), or a service provider can send targeted advertisements based on a user's area. Prior to standardized LCS, such capabilities would require proprietary, non-interoperable solutions. NI-LR, as part of the broader 3GPP LCS framework, created a unified, secure, and privacy-protected method for network-initiated positioning, enabling global interoperability for safety and commercial applications.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (122 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the NI-LR function was enhanced to support obtaining location information from trusted and untrusted WLAN access networks and to introduce high-accuracy location estimates. Furthermore, assistance data for the OTDOA positioning method was extended for New Radio (NR), and procedures were specified to distinguish the location source when a sensor-based positioning method is used.
In Release 16, the NI-LR function was enhanced by clarifying and completing several core procedures, including the commercial 5GC-MT-LR procedure and the unified location service exposure procedure. It also introduced support for new operational capabilities such as concurrent location requests and exception support for periodic or triggered location reporting. Furthermore, the release provided corrections and improvements for low-power periodic location and refined the authorization and privacy checks between the GMLC and NEF.
- Support of Concurrent Location Request TS 23.273CR0006
- Clarification on positioning access selection in the 5GC-MO-LR procedure TS 23.273CR0008
- Correction and Improvement of Low Power Periodic and Triggered Location TS 23.273CR0011
- Handling of NG-RAN Location Service Exposure Procedure TS 23.273CR0021
- Clarification of 5GC-MT-LR procedure for the commercial location service TS 23.273CR0024
- Completion of 5GC-MO-LR Procedure for TS 23.273 TS 23.273CR0025
+ 26 more changes
In Release 17, the NI-LR function was updated to support a Scheduled Location Time for bulk operations and to include a higher resolution timestamp for location estimates. The procedure was also enhanced to support multiple QoS classes in deferred location requests and to allow for the usage of a requested maximum age of location information. Furthermore, requirements for GNSS integrity and an indication for reliable UE location information were added to the location request.
- Introduction of the Scheduled Location Time TS 23.273CR0187
- Addition of a Scheduled Location Time TS 23.273CR0151
- Higher Resolution Timestamp for Location Estimates TS 29.515CR0059
- Schedule location time for GMLC TS 29.515CR0072
- Scheduled location time for bulk operation TS 29.515CR0079
- NMEA GGA sentence info in high accuracy GNSS location estimates [HA-GNSS-NMEA] TS 37.355CR0349
+ 19 more changes
In Release 18, the NI-LR function was enhanced to support location service continuity between EPS and 5GS in both directions for deferred Mobile Terminating Location Requests. It also introduced the capability for the NWDAF to act as a GMLC services consumer, requiring a new privacy check when the NWDAF requests UE location from the GMLC. Furthermore, Release 18 added support for a local LMF and GMLC selection as a new feature.
- Multiple location report for MT-LR Immediate Location Request for the regulatory service TS 23.273CR0237
- Support of Mobile Base Station Relay for Location Service TS 23.273CR0240
- UE location reporting only when the UE locates in the target area defined with finer granularity TS 23.273CR0242
- Privacy Check for NWDAF requesting UE location from GMLC TS 23.273CR0249
- Introduce new feature: local LMF and GMLC selection TS 23.273CR0254
- Verification of location for NTN access TS 23.273CR0258
+ 44 more changes
In Release 19, the NI-LR function was enhanced with a new deferred procedure for periodic location events based on NRPPa periodic measurement reports. It also introduced support for multiple location reports specifically for next-generation emergency routing scenarios. Furthermore, the release added control parameters for an on-demand posSIB request mechanism.
- Adding Deferred 5GC-MT-LR Procedure for Periodic Location Events based NRPPa Periodic Measurement Reports TS 23.273CR0589
- Multiple Location Report for Next Generation Emergency Routing TS 23.273CR0608
- Add message flow of converged charging for 5GC-MO-LR TS 32.271CR0032
- UE request for equalIntegerAmbiguityLevel assistance data [GNSS-EqualIntegerAmbiguity] TS 37.355CR0557
- Introduction of control parameters for on-demand posSIB request [OdPosSIB_Req] TS 38.305CR0191
- Support of Location Service Involving WAB-Nodes TS 38.305CR0196
+ 5 more changes
Explore further
Broader topics and technologies where NI-LR plays a role.
Defining Specifications
3GPP specifications that define or reference NI-LR, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 03.071 v7b0 | Location Services (LCS) Stage 2 Description | Rel-7 |
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TS 23.171 v1300 | LCS Stage 2 Specification for UMTS | Rel-4 |
| TS 23.271 vj00 | LCS Stage 2 Specification | Rel-19 |
| TS 23.273 vj50 | 5G Location Services Stage 2 Architecture | Rel-19 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TR 23.730 ve00 | Study on extended CIoT architecture | Rel-14 |
| TS 29.171 vj00 | LCS Application Protocol (LCS-AP) Specification | Rel-19 |
| TS 29.515 vj50 | Ngmlc Service Based Interface Protocol | Rel-19 |
| TS 32.250 vj00 | Circuit Switched Offline Charging | Rel-19 |
| TS 32.251 vj00 | PS Domain Charging Management | Rel-19 |
| TS 32.271 vj20 | 3GPP LCS Charging Management Spec | Rel-19 |
| TS 32.272 vj00 | Charging for Push-to-Talk over Cellular (PoC) | Rel-19 |
| TS 32.293 vj00 | Proxy Function in Domestic Service Provider | Rel-19 |
| TS 36.305 vj00 | UE Positioning in E-UTRAN Stage 2 | Rel-19 |
| TS 36.355 vj00 | LTE Positioning Protocol (LPP) | Rel-19 |
| TS 37.355 vj20 | LTE Positioning Protocol (LPP) | Rel-19 |
| TS 37.571 vj00 | UE Conformance for Positioning | Rel-19 |
| TS 38.305 vj00 | NG-RAN UE Positioning Stage 2 | Rel-19 |