Description
The Location Management Server (LMS) is a functional entity within the 3GPP Location Services (LCS) architecture, introduced as part of the broader evolution towards more flexible and service-based core networks. It is defined as a component that can be deployed within the 5G Core (5GC) or adapted for other architectures. The LMS centralizes the management of location-related data and logic that was previously more distributed among other Network Functions (NFs) like the Gateway Mobile Location Centre (GMLC). Its primary role is to store and handle location service subscriptions, user privacy settings (LCS Client authorizations), and subscriber location data or pointers to such data.
Architecturally, the LMS interacts with other core network functions via service-based interfaces (e.g., Nlmf interface). Key interactions include communication with the Access and Mobility Management Function (AMF) for obtaining location estimates from the access network, with the Unified Data Management (UDM) for subscriber data, and with external Location Service Clients (e.g., from a third-party application or an internal network service). The LMS may store permanent or temporary location information, geofencing definitions, and triggering events for periodic or event-driven location reporting. It implements the logic for evaluating location-based triggers and notifying authorized clients when conditions are met.
How it works: When a location request is received from an authorized LCS Client, the LMS validates the request against the target user's privacy profile. If authorized, it determines the appropriate method to obtain the location. This could involve querying the AMF, which in turn may initiate signaling with the Radio Access Network (RAN) and the UE (using protocols like LTE Positioning Protocol (LPP)) to generate a location estimate using GNSS, OTDOA, or other positioning methods. The LMS then formats and returns the location information to the requesting client. For deferred or triggered location requests, the LMS stores the trigger criteria and manages the ongoing monitoring, initiating location retrievals as needed and sending notifications. By centralizing this management, the LMS simplifies service logic, enhances scalability, and provides a unified point for applying privacy policies and service-level agreements for location information.
Purpose & Motivation
The LMS was created to address the growing complexity and demand for location-based services in mobile networks, which extended far beyond basic emergency caller location. Previous LCS architectures, centered on the GMLC, were often monolithic and tightly coupled with circuit-switched or early packet core elements. As networks evolved towards cloud-native, service-based architectures (SBA) with 5GC, there was a need to decompose functions for greater flexibility, scalability, and independent innovation. The LMS embodies this decomposition by extracting the location management, subscription, and privacy logic into a dedicated, scalable network function.
This separation solves several problems: it allows for more efficient handling of massive numbers of location requests from IoT devices and commercial applications; it provides a clear, standardized interface for application developers to access network location capabilities; and it centralizes the critical privacy control function, which is increasingly important due to regulations like GDPR. The creation of the LMS was motivated by use cases such as connected vehicles, asset tracking, location-based alerts, and enhanced emergency services (e.g., Advanced Mobile Location), which require reliable, low-latency, and policy-controlled access to device location. It enables network operators to offer location as a managed platform service with differentiated QoS and security levels, often in conjunction with network slicing for specific vertical industries.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (110 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the Location Management Server (LMS) function was newly integrated into the Public Land Mobile Network (PLMN) architecture, as indicated by the CR title "Location Server integration to PLMN." This integration establishes the LMS as a core network function within the 3GPP-defined LCS network for providing location services. Furthermore, the release introduced procedures for an MC server to initiate group de-affiliation, both within its home system and from groups in a partner system.
- Introduction of MC server initiated group de-affiliation procedure TS 23.280CR0026
- MC server initiated group de-affiliation from group(s) in partner system TS 23.280CR0053
- Resource Management in CFA TS 23.280CR0059
- Priority between MC service servers TS 23.280CR0071
- Request for resources from MC service server TS 23.280CR0091
- Functional alias controlling role of MC service server TS 23.280CR0106
+ 5 more changes
In Release 16, the Location Management Server (LMS) function was enhanced to support **location information reporting and subscription based on a functional alias**, a new concept for identifying users. Furthermore, the release introduced **IWF alignment for talker location** across various call types, including Group call, Private call, and Chat group, ensuring consistent location data delivery in interworking scenarios. These updates also included the addition of location information to specific IWF floor control messages and refinements to location subscription procedures.
- 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
+ 12 more changes
In Release 17, the LMS function introduced several new capabilities focused on enhancing location reporting and management for Mission Critical services. Key additions included support for location history reporting, with procedures for its configuration, cancellation, and status reporting, as well as the introduction of an MC service UE label for location reporting to provide additional context. The release also delivered clarifications and additional details to existing location information reports, notifications, and reporting procedures to improve functionality and accuracy.
- Providing activated functional alias information to the group controlling server TS 23.280CR0207
- 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
+ 17 more changes
In Release 18, the LMS function was enhanced to enable the sharing of location information across interconnected Mission Critical (MC) systems, supporting on-demand, triggered, and subscription-based procedures. New capabilities were introduced to allow a user to restrict the dissemination of their location information, and the LMS was given access to all MCX user profiles. Furthermore, the release added support for location information requests for both talker-to-party and party-to-talker requests, aligning with security specifications.
- MCGWUE 3GPP access network related location information management TS 23.280CR0300
- 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
- Sharing location information across MC systems (subscription) TS 23.280CR0325
- Sharing location information across MC systems (configuration) TS 23.280CR0326
+ 19 more changes
In Release 19, the LMS function introduced new procedures including a client-triggered location reporting cancel procedure and a trigger override and cancel trigger override procedure for location reporting. Enhancements were made for location reporting configuration and for requesting specific location information of an MC service user on-demand or periodically. The release also added support for Location-related UE Group Analytics and defined the interface between the MC service server and the Recording server.
- ACM Group configuration management TS 23.280CR0466
- ACM user migration management TS 23.280CR0507
- 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
- Client-triggered location reporting cancel procedure TS 23.280CR0605
- Requesting specific location information of MC service user on-demand or periodic TS 23.280CR0609
+ 23 more changes
In Release 20, the LMS (Location Management Server) function was enhanced with revised procedures for event-triggered location reporting and new, specified interactions with the MC Service Server. These updates also included corrections to general location management and to the LMR (Location Management for MCData Relay) key management messages, ensuring they apply correctly only to the MCData service.
- Enhancing event triggered location reporting procedures TS 23.280CR0723
- Revised CSC-15: Incorporating Additional LMS and MC Service Server Interactions TS 23.280CR0671
- Corrections to location management TS 23.280CR0699
- Correction for LMR Key Management Messages to apply only to MCData service TS 23.283CR0101
Explore further
Broader topics and technologies where LMS plays a role.
Defining Specifications
3GPP specifications that define or reference LMS, 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 23.436 vk00 | ADAEnabler Functional Architecture and Information Flows | Rel-20 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TS 24.257 vj40 | UAS Application Enabler (UAE) Layer | Rel-19 |
| TS 33.127 vj50 | Lawful Interception Architecture and Functions | Rel-19 |
| TS 38.811 vf40 | Study on NR Support for Non-Terrestrial Networks | Rel-15 |