Description
The Location Management Client (LMC) is a functional entity defined within the 3GPP service-based architecture for location services. It acts as a requestor and consumer of location information. The LMC can be implemented within a User Equipment (UE), an Application Function (AF), or other network entities that require location data. Its primary role is to initiate location requests towards the network's location management system, specifically the Location Management Function (LMF) or the Gateway Mobile Location Centre (GMLC), depending on the architecture and service scenario. The LMC formulates location service requests, which can include parameters such as the target UE's identifier, the required Quality of Service (e.g., accuracy, response time), and the type of location information needed (e.g., immediate location, periodic tracking, or triggered reporting).
Upon sending a request, the LMC communicates over standardized service-based interfaces, such as Nlmf_Location or N5g-eir_LocationReporting, to the appropriate network function. The network processes the request, which may involve coordinating with the Radio Access Network (RAN) and the UE itself to perform positioning measurements using techniques like Observed Time Difference of Arrival (OTDOA), Uplink Time Difference of Arrival (UTDOA), or Assisted Global Navigation Satellite System (A-GNSS). Once the location is determined, the network delivers the location estimate or report back to the LMC.
The LMC's architecture is designed to be flexible, supporting both UE-based and network-based location procedures. In UE-based scenarios, the LMC within the UE may interact directly with the LMF to obtain assistance data for positioning or to report its own calculated location. In AF-based scenarios, an external application server (hosting the LMC) requests location information for a target UE, enabling services like fleet tracking, emergency services, or location-based advertising. The LMC abstracts the complexities of the underlying positioning technologies from the application, providing a standardized API for location service consumption.
Key components of the LMC's operation include its service interface bindings, security context for authenticating and authorizing location requests, and its ability to handle different location service types defined in 3GPP, such as Mobile Terminated Location Request (MT-LR), Mobile Originated Location Request (MO-LR), and Network Induced Location Request (NI-LR). Its role is crucial for enabling the 5G location service ecosystem, ensuring that applications can reliably and securely access UE location data while respecting privacy regulations and network policies.
Purpose & Motivation
The LMC was introduced to standardize and simplify the client-side interface for accessing network-based location services in 5G and beyond. Prior to its definition, location service requests from applications or UEs often relied on proprietary or less integrated methods, leading to fragmentation and increased complexity for application developers and network operators. The LMC provides a unified, service-based approach aligned with the 5G Core Network's architectural principles.
Its creation was motivated by the growing demand for precise, low-latency location services across various verticals, including industrial IoT, automotive (V2X), augmented reality, and public safety. These applications require a reliable and efficient mechanism to request and receive location data. The LMC addresses this by offering a standardized client function that can be embedded in different entities (UEs, AFs), facilitating interoperability and enabling new business models for location-based services.
Furthermore, the LMC supports regulatory requirements, such as enhanced emergency caller location (e.g., for E911 in the US or E112 in Europe), by providing a defined path for emergency service applications to request UE location. It also enhances privacy and security by integrating with 3GPP's authentication and authorization frameworks, ensuring that location information is only disclosed to authorized clients under permitted conditions.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (81 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the Location Management Client (LMC) was introduced as a constituent client function within the broader MC client, specifically to enable location services for Mission Critical systems. This introduction was part of the architecture enabling an MC gateway UE to provide access for non-3GPP devices, where the LMC interacts with a corresponding Location Management Server. The release also defined supporting functional entities, such as the GW Client and GW Server, to facilitate location management for MC clients residing on non-3GPP user equipment.
In Release 16, the LMC function was enhanced to support location reporting and management based on a **functional alias**, enabling new procedures for interworking with Land Mobile Radio (LMR) systems. Furthermore, location information was integrated into key Interworking Function (IWF) messaging for floor control and call setup across group, private, and imminent peril communications. The release also introduced the provisioning of the **Location Management Server URI** as part of the initial MC service UE configuration.
- Implicit functional alias management TS 23.280CR0188
- Change to Location Subscription for notification immediate TS 23.280CR0196
- Location information reporting based on functional alias TS 23.280CR0203
- Functional Alias management for interworking between MC service system and LMR system TS 23.283CR0035
- Proposal for affiliation status information in group management server TS 23.280CR0165
- Add Location information to IWF floor request and IWF floor taken messages TS 23.283CR0022
+ 11 more changes
In Release 17, the LMC function was enhanced with new capabilities for location history reporting, including configuration, cancellation, and status reporting procedures. It also introduced the "MC service UE label" for location reporting to better identify users within Mission Critical services. Furthermore, the release provided additional details and clarifications for location information reports, notifications, and emergency alert requests.
- Additional details to the Location information report TS 23.280CR0243
- Additional details to the Location information notification TS 23.280CR0244
- Additional details to the Location report response TS 23.280CR0245
- Additional details to the Location reporting procedures TS 23.280CR0246
- Configuration location history reporting TS 23.280CR0251
- Cancel location history transmission TS 23.280CR0252
+ 11 more changes
In Release 18, the LMC (Location Management Client) function was enhanced to support sharing location information across interconnected Mission Critical (MC) systems through new subscription, on-demand, and triggered procedures. It also introduced support for MC clients residing on non-3GPP devices via the MC gateway UE function and added user controls to restrict the dissemination of location information. Furthermore, the release defined procedures for the disconnection between an MC gateway UE and its MC client.
- MCGWUE 3GPP access network related location information management TS 23.280CR0300
- MCGWUE_MBMS support for MC clients residing on non-3GPP devices TS 23.280CR0301
- MC gateway UE – MC client disconnection procedure TS 23.280CR0311
- Sharing location information across MC systems (functional model) TS 23.280CR0322
- Sharing location information across MC systems (on-demand) TS 23.280CR0323
- Sharing location information across MC systems (triggered) TS 23.280CR0324
+ 10 more changes
In Release 19, the Location Management Client (LMC) function introduced new procedures for client-triggered location reporting cancellation and for overriding or canceling location reporting triggers. Enhancements were also made to allow on-demand or periodic requests for specific user location information and to manage location reporting configurations for multiple logon devices. Furthermore, the release provided clarifications and corrections for procedures involving functional aliases and event-triggered location notifications across MC systems.
- ACM client user profile configuration data TS 23.280CR0430
- ACM Group configuration management TS 23.280CR0466
- ACM user migration management TS 23.280CR0507
- Adding authorized actions to ACM client user profile configuration data TS 23.280CR0565
- MC service group ID(s) usage for location information request TS 23.280CR0532
- Location reporting information obtained from the PLMN operator (LTE) TS 23.280CR0569
+ 20 more changes
In Release 20, the enhancements for the Location Management Client (LMC) primarily focused on refining event-triggered location reporting procedures and implementing corrections to location management. A specific correction was also made to ensure that certain Key Management Messages for Location Measurement Reports apply exclusively to the MCData service, clarifying and tightening the scope of this functionality.
Explore further
Broader topics and technologies where LMC plays a role.
Defining Specifications
3GPP specifications that define or reference LMC, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 23.280 vk10 | Common Architecture for Mission Critical Services | Rel-20 |
| TS 23.283 vk00 | Mission Critical Communication Interworking | Rel-20 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |