Description
Location Deferred Request (LDR) is a feature of the 3GPP Location Services (LCS) system. It operates within the standardized LCS architecture, which involves a LCS Client, a LCS Server (typically the Gateway Mobile Location Centre - GMLC), and the core network nodes (e.g., MSC, SGSN, MME) interacting with the radio access network and the UE. The LDR mechanism allows an authorized LCS Client to submit a location request with a deferred reporting condition. Instead of triggering an immediate location procedure, the network stores the request and activates it when the specified condition is met. The key components involved include the deferred location request parameters stored in the network (e.g., in the GMLC or a dedicated service node), timers, and event triggers. The request specifies criteria such as a single future absolute time, a periodic interval (e.g., every hour), or a change in area event (e.g., when the UE enters or leaves a defined geographical area). When the triggering condition occurs, the network executes the standard location determination procedure, which could be network-based (e.g., using timing advance or observed time difference of arrival), UE-based (using GNSS like GPS), or assisted/hybrid methods. Once the location is obtained, the network delivers the result (e.g., geographic coordinates) to the requesting LCS Client according to the deferred request's delivery instructions. This process decouples the request from the immediate network and UE resource usage for positioning, allowing for more efficient scheduling and battery-friendly operation for the UE, especially for non-urgent tracking applications. The feature relies on the network's ability to manage and correlate multiple deferred requests, handle their lifecycle (creation, activation, execution, cancellation), and ensure privacy and security as per subscriber consent.
Purpose & Motivation
Location Deferred Request was created to expand the utility of cellular location services beyond simple, immediate "where are you now" queries. Early LCS capabilities were primarily real-time, which limited applications to instant navigation, emergency services (E911), and similar time-critical uses. Many commercial and enterprise applications, however, require location information on a scheduled or event-driven basis without constant active polling. Examples include fleet management for periodic position logging, asset tracking for theft recovery (reporting location only upon movement), location-based advertising triggered by entering a shopping mall, or parental controls that alert when a child leaves a safe zone. Performing these with continuous real-time requests would be highly inefficient, consuming excessive network signaling resources, core network processing capacity, and UE battery life. LDR solves this by allowing a single request to define a future action plan. This reduces signaling overhead, optimizes network resource utilization, and is more considerate of UE power constraints. It enabled a new class of location-based services that are proactive, scheduled, or event-triggered, forming a foundational capability for the Internet of Things (IoT) and Machine-to-Machine (M2M) tracking use cases that emerged later. Its introduction in the R99 timeframe positioned GSM and UMTS networks to offer sophisticated value-added services.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (217 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the LDR (Location Deferred Request) function was newly introduced, enabling deferred location reporting through procedures like the Location Service ProvideLocationInfo and ProvidePositioningInfo. This allowed the network to request and receive location information for a target UE at a later time, separate from an immediate location request. The introduction of the GMLC URI for the Namf_Location EventNotify service and the handling of a Location header in responses were key supporting enhancements for this deferred capability.
- Remove AN Type from N1/N2 Message Transfer Request TS 29.518CR0008
- Location Service ProvideLocationInfo TS 29.518CR0019
- Location Service ProvidePositioningInfo TS 29.518CR0020
- Clarification on location information in immediate report TS 29.518CR0049
- SMF Reallocation requested Indication TS 29.518CR87
- N1N2MessageTransfer Request message TS 29.518CR123
+ 5 more changes
In Release 16, the key new capabilities for the Location Deferred Request (LDR) function included the formal completion and clarification of the deferred 5GC-MT-LR procedure, including support for its cancellation. This release also introduced the AMF and LMF service operations specifically for handling a commercial and deferred 5GC-MT-LR, enabling the AMF to forward location services messages between the UE and LMF. Furthermore, it added operations for location privacy setting and enhanced the unified location service exposure procedure.
- Support of Concurrent Location Request TS 23.273CR0006
- Adding Location Privacy Setting operation TS 24.571CR0001
- Target Access type in N1N2MessageTransfer Request for a MA PDU session TS 29.518CR0229
- User location report TS 29.518CR0241
- AMF Location Service Operations for a Commercial and Deferred 5GC-MT-LR TS 29.518CR0262
- Location Service ProvidePositioningInfo TS 29.518CR0264
+ 48 more changes
In Release 17, the key enhancement for the Location Deferred Request (LDR) function was the introduction of the "Scheduled Location Time" capability, allowing a location request to specify a precise future time for obtaining the location estimate. This was complemented by providing a higher resolution timestamp for the location estimates themselves. These additions enabled new use cases like bulk operations and trend analysis by allowing the network to schedule and return location information at a defined time.
- Introduction of the Scheduled Location Time TS 23.273CR0187
- Addition of a Scheduled Location Time TS 23.273CR0151
- Add timestamp of location estimate TS 24.080CR0076
- Scheduled location time TS 24.080CR0078
- Add scheduled location time in LCS-MOLRArg TS 24.080CR0093
- Additional of Scheduled Location Time TS 24.571CR0012
+ 48 more changes
In Release 18, the LDR (Location Deferred Request) function was enhanced to enable location service continuity for deferred Mobile Terminated Location Requests (MT-LR) between EPS and 5GS in both directions. It also introduced an additional check in the target area for deferred area events, allowing for UE location reporting with finer granularity only when the UE is located within the defined target area. Furthermore, support was added for the MT-LR procedure when a Mobile Base Station Relay (MBSR) is involved in locating a UE.
- 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
+ 68 more changes
In Release 19, the LDR function was enhanced with a new deferred 5GC-MT-LR procedure for periodic location events based on NRPPa periodic measurement reports. It also introduced a UE location trends report at RAN node granularity and provided clarifications for operations when a UE is served by an MWAB-gNB and for the LMF requesting an ML model from the NWDAF. Additionally, corrections and updates were made to procedures like SL-MT-LR for periodic triggered events and the handling of the LocationPrivacySetting return result.
- 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
- UE Location Trends Report at RAN Node Granularity TS 29.518CR1162
- Clarification on LMF requesting ML model for LMF-based AI/ML Positioning from the NWDAF containing MTLF TS 23.273CR0657
- Clarification of location services when a UE is served by a MWAB-gNB TS 23.273CR0670
- Inter PLMN GMLC communication via NEF removal TS 23.273CR0736
+ 18 more changes
Explore further
Broader topics and technologies where LDR plays a role.
Defining Specifications
3GPP specifications that define or reference LDR, 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 |
| 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 |
| TS 23.731 vg00 | 5G LCS Architecture Enhancement Study | Rel-16 |
| TS 24.080 vj20 | Mobile radio interface layer 3 supplementary services | Rel-19 |
| TS 24.571 vj20 | Control Plane LCS Procedures | Rel-19 |
| TR 26.926 vj00 | Traffic Models & Quality Evaluation for Media/XR in 5G | Rel-19 |
| TS 29.515 vj50 | Ngmlc Service Based Interface Protocol | Rel-19 |
| TS 29.518 vj50 | AMF Service Based Interface Protocol | Rel-19 |
| TS 29.572 vj50 | Nlmf Service Based Interface Stage 3 | Rel-19 |