3GPP NTN Roadmap: From Release 15 to Release 19 and Beyond
- Neeraj Verma
- 5 minutes ago
- 9 min read
Introduction 3GPP NTN Roadmap
3GPP NTN Roadmap Non-Terrestrial Networks (NTNs) have become an important part of the evolution of modern cellular communication systems.
The 3rd Generation Partnership Project (3GPP) formally introduced NTN as a new feature in Release 17 (R17). However, the development of NTN did not begin with Release 17. Significant preparatory studies and research activities were carried out in earlier releases, particularly Release 15 (R15) and Release 16 (R16).
The work has continued to evolve through Release 18 (R18), Release 19 (R19), and beyond, with each release introducing new capabilities and enhancements.
The overall evolution can be summarized as:3GPP NTN Roadmap
R15 → R16 → R17 → R18 → R19 → Beyond
Each stage established important foundations for the integration of satellite and other non-terrestrial platforms with 5G and future cellular networks.3GPP NTN Roadmap
Release 15 (R15): Beginning of NTN Studies
The 3GPP started formal work related to NTN in 2017, during Release 15.
A Study Item was initiated in 3GPP RAN Working Group 1 (RAN1).
The primary focus was on:
NTN deployment scenarios
NTN channel models
Propagation characteristics
Radio-related aspects of NTN
Why Were New Channel Models Needed?
An NTN does not have the same propagation characteristics as a conventional Terrestrial Network (TN).
In a terrestrial network, the radio signal generally travels between a ground-based base station and the user equipment.
In an NTN, the communication path can involve a satellite or other airborne platform operating at a significant altitude.
This introduces unique characteristics such as:
Long propagation distances
Different propagation delays
Doppler effects
Different channel conditions
Large coverage areas
Therefore, new NTN-specific channel models were required for analyzing and evaluating NTN systems.
The R15 studies established an important technical foundation for subsequent NTN development.
Release 16 (R16): Use Cases and NR Support Studies
Release 16 expanded the NTN-related work significantly.
The 3GPP Service and System Aspects (SA) working groups studied use cases for satellite-based NTN as part of the broader study on satellite access in 5G.
The studies identified three major categories of NTN use cases:
1. Service Continuity
Maintaining communication services when users move outside terrestrial network coverage.
2. Service Ubiquity
Providing connectivity across areas where terrestrial networks are unavailable or difficult to deploy.
3. Service Scalability
Efficiently supporting services across large geographical areas.
These three categories became important foundations for understanding the motivation and requirements for satellite-based NTN.
R16 Radio Access Network Studies
The RAN working groups also carried out a comprehensive study on solutions for supporting NTN using 5G New Radio (NR).
The objective was to determine what changes and additional features were required for NR to operate effectively over an NTN environment.
The studies examined the unique requirements introduced by:
Satellite propagation
Large coverage areas
Long propagation delays
Doppler effects
Timing differences
Satellite mobility
These studies established a baseline for the later normative NR-NTN work in Release 17.
In particular, they provided the foundation for supporting a transparent NTN payload.
Release 17 (R17): NTN Becomes a 3GPP Feature
Release 17 represents a major milestone in the NTN roadmap.
For the first time, 3GPP formally introduced NTN as a new feature by developing specifications for NR-based NTN.
The R17 specifications established a strong foundation for future NTN enhancements.
The initial R17 NR-NTN specifications were based on two important assumptions:
The UE has Global Navigation Satellite System (GNSS) capability.
The NTN uses a transparent payload.
Major NR-NTN Enhancements in R17
Because NTN has characteristics that differ from terrestrial networks, several enhancements were required in the existing NR specifications.
Important areas addressed in R17 include:
Synchronization
NTN introduces unique timing and synchronization requirements due to the long communication path and satellite movement.
Timing Adjustments
Additional mechanisms are required to compensate for the propagation characteristics of NTN links.
System Information
System information procedures were enhanced to support NTN-specific requirements.
Protocol Timers
Protocol timers needed adjustments to accommodate longer delays associated with NTN communication.
Hybrid Automatic Repeat Request (H-ARQ)
H-ARQ operation required enhancements because NTN propagation delays can be significantly different from terrestrial networks.
Timing and Frequency Pre-Compensation
UEs may need to perform timing and frequency pre-compensation to account for propagation delay and Doppler effects.
Tracking and Registration Area Management
NTN coverage areas and satellite movement introduce additional requirements for tracking and registration management.
Handover
Satellite movement and large coverage areas create unique handover requirements.
Quality of Service (QoS)
QoS mechanisms need to account for NTN-specific network characteristics.
User Location Reporting
NTN systems require appropriate mechanisms for handling and reporting UE location information.
Feeder Link Management
Management of the communication link between the NTN payload and the NTN Gateway is another important NTN-specific area.
R17 3GPP SA2 Architecture Work
The 3GPP Service and System Aspects Working Group 2 (SA2) also conducted important work related to satellite access in 5G.
The objective was to identify key architectural issues associated with satellite-based NTN and develop solutions for:
Direct satellite access
Satellite backhaul
The R17 SA2 normative work addressed several important areas.
These included:
Mobility management with large coverage areas
Mobility management with moving coverage areas
Satellite-related delay
QoS with satellite access
QoS with satellite backhaul
RAN mobility with non-geostationary orbit (NGSO) regenerative-based satellite access
Regulatory services involving supranational satellite ground stations
This work helped establish the architectural foundation for integrating satellite connectivity into the broader 5G system.
R17 Management and Orchestration
The 3GPP SA Working Group 5 (SA5) addressed management and orchestration aspects associated with NTN.
This is important because NTN introduces additional network elements and operational requirements compared with conventional terrestrial networks.
Management and orchestration are necessary for coordinating the network and its resources effectively.
R17 Core Network and Terminal Work
The 3GPP Core Network and Terminals (CT) working groups also studied aspects of the 5G Core (5GC) architecture for satellite networks.
The Release 17 work in the CT working groups included considerations related to:
Public Land Mobile Network (PLMN) selection
PLMN selection becomes particularly important when users may have access to both terrestrial and satellite-based network services.
Release 17 IoT-NTN
Release 17 did not focus only on NR-NTN.
3GPP also worked on IoT-NTN.
This work built on previously defined Release 13 technologies:
NB-IoT
eMTC
Also known as LTE-M
Enhancements were introduced to support these technologies in NTN environments.
IoT-NTN and the EPC
Because NB-IoT and eMTC are based on 4G LTE specifications, IoT-NTN uses the 4G Evolved Packet Core (EPC) rather than the 5G Core.
The IoT-NTN work used the studies and specifications developed for NR-NTN as a baseline and then introduced additional enhancements specific to:
NB-IoT
eMTC/LTE-M
Therefore, Release 17 established two important NTN technology paths:
NR-NTN
and
IoT-NTN
Release 18 (R18): NTN Enters 5G-Advanced
The evolution of NTN continued in Release 18.
Release 18 and subsequent releases are associated with the evolution of 5G-Advanced.
The objective was to enhance the capabilities established in Release 17 and address additional use cases and performance requirements.
Key NR-NTN Enhancements in R18
Several important improvements were introduced for NR-NTN.
Coverage Enhancement
R18 aims to enhance coverage to support services such as:
Voice
Low-rate data services
This expands the potential service capabilities of NTN.
Mobility and Service Continuity
Enhancements were introduced for mobility between:
Terrestrial Network ↔ Non-Terrestrial Network
These improvements help support more continuous service as users move between TN and NTN coverage.
Support for Frequencies Above 10 GHz
R18 also addresses NTN operation at frequencies greater than 10 GHz.
This expands the potential frequency range and deployment possibilities for NTN systems.
UE Location Verification
Network-based verification of the UE location is another important NTN enhancement.
This can be particularly relevant because satellite systems have unique geographical and regulatory considerations.
R18 IoT-NTN Enhancements
Release 18 also introduced enhancements for IoT-NTN.
Discontinuous Coverage
One important enhancement is support for scenarios where NTN coverage is not continuously available.
For example, a UE may move between:
NTN Coverage Area → No NTN Coverage → NTN Coverage
The network needs mechanisms to handle such discontinuous coverage conditions.
Mobility Enhancements
R18 also introduces mobility-related improvements, including support for neighbor cell measurements.
These enhancements help IoT devices operate more effectively in changing NTN coverage environments.
Performance Enhancements
Other performance improvements include:
Disabling H-ARQ feedback where appropriate
Improved GNSS operations
These changes are intended to improve NTN IoT performance and operational efficiency.
Release 19 (R19) and Beyond
The NTN roadmap continues into Release 19 and future releases.
At the 3GPP Release 19 workshop held in June 2023, NTN was identified as one of the candidate areas for normative specifications in Release 19.
The Release 19 work began in summer 2024, with completion targeted for late 2025.
R19 continues the evolution of both NR-NTN and IoT-NTN.
R19 NR-NTN Enhancements
The Release 19 NR-NTN work focuses on several important areas.
Enhanced Downlink Coverage
One objective is to improve the coverage available on the downlink.
Enhanced Uplink Capacity
R19 also targets improvements in NTN uplink capacity.
Multimedia Broadcast Service (MBS)
Support for Multimedia Broadcast Service (MBS) is another important area.
MBS can enable efficient distribution of multimedia content to multiple users.
5G Network Functions on the NTN Platform
Another major direction is supporting selected 5G Network Functions (NFs) on the NTN platform.
This includes support for a regenerative payload.
This represents an evolution beyond the transparent payload approach used in the initial NTN architecture.
RedCap Support
R19 also targets support for Reduced Capability (RedCap) UEs.
This can expand NTN applicability to additional classes of 5G devices and applications.
R19 IoT-NTN Phase 3
Release 19 also includes further development of IoT-NTN Phase 3.
Two key enhancements include:
Store and Forward
Store-and-forward capabilities can help support scenarios where continuous end-to-end connectivity is not available.
Data can be stored and subsequently forwarded when the necessary communication path becomes available.
Uplink Capacity Enhancement
Another major objective is to improve IoT-NTN uplink capacity.
This is important as the number of connected IoT devices and the amount of uplink data continue to increase.
NTN Roadmap at a Glance
Release | Major NTN Development |
R15 | NTN deployment scenarios and channel models |
R16 | NTN use cases and NR support studies |
R17 | NTN formally introduced; NR-NTN and IoT-NTN specifications |
R18 | 5G-Advanced NTN enhancements |
R19 | Advanced NR-NTN and IoT-NTN Phase 3 enhancements |
Beyond R19 | Continued evolution toward increasingly integrated NTN and future 6G networks |
Evolution from Study to Standardization
The 3GPP NTN roadmap demonstrates a clear progression.
R15 — Understand NTN
The initial focus was on understanding NTN deployment scenarios and developing appropriate channel models.
R16 — Study Requirements
3GPP investigated NTN use cases and studied what NR needed to support NTN.
R17 — Standardize NTN
NTN became a formal 3GPP feature with normative specifications for NR-NTN and IoT-NTN.
R18 — Enhance NTN
The technology evolved into 5G-Advanced with improvements in coverage, mobility, frequency support, location verification, and IoT performance.
R19 — Expand NTN Capabilities
The roadmap moves toward enhanced coverage and capacity, MBS, regenerative payloads, RedCap support, store-and-forward, and additional IoT improvements.
Transparent to Regenerative Payload Evolution
One particularly important direction in the NTN roadmap is the evolution from transparent payloads toward support for regenerative payloads.
In the initial R17 architecture, the NTN payload is primarily transparent and performs functions such as RF filtering, frequency conversion, and amplification.
Future architectures can introduce more processing capability directly on the NTN platform.
A regenerative payload can therefore support selected network functions on the NTN platform itself.
This represents an important architectural evolution for future NTN systems.
Why the 3GPP NTN Roadmap Matters
The NTN roadmap demonstrates that satellite connectivity is becoming increasingly integrated into the cellular ecosystem.
Rather than treating satellite communication as an entirely separate technology, 3GPP is progressively developing mechanisms that allow NTN to work with:
5G NR
5G Core
IoT technologies
Terrestrial networks
Advanced mobility mechanisms
Future network functions
This integration is essential for creating more ubiquitous and flexible communication networks.
NTN and the Road to 6G
Although the major NTN standardization work has been associated with 5G and 5G-Advanced, the evolution of NTN also provides an important foundation for future 6G networks.
Future communication systems are expected to integrate terrestrial, airborne, and spaceborne connectivity more closely.
The progression from:
R15 Studies → R16 Studies → R17 NTN → R18 5G-Advanced → R19 Enhancements → Future Releases
illustrates how NTN is gradually becoming a fundamental part of the broader cellular ecosystem.
Conclusion
The 3GPP NTN roadmap represents a multi-release evolution rather than a technology that appeared suddenly in Release 17.
The journey began with Release 15, where 3GPP studied NTN deployment scenarios and developed NTN-specific channel models.
In Release 16, 3GPP studied satellite-based NTN use cases and the solutions required for NR to support NTN.
Release 17 marked the major milestone where NTN became a formal 3GPP feature, with specifications for both NR-NTN and IoT-NTN.
Release 18 continued the evolution through 5G-Advanced, introducing improvements in coverage, TN-NTN mobility, service continuity, higher-frequency operation, UE location verification, and IoT performance.
Release 19 and beyond continue to expand NTN capabilities through enhanced downlink coverage, uplink capacity, MBS, regenerative payload support, RedCap, store-and-forward capabilities, and further IoT-NTN enhancements.
The overall roadmap demonstrates one clear direction:
NTN is evolving from an experimental and specialized satellite-access technology into an increasingly integrated component of modern cellular networks.
Understanding this roadmap is essential for telecom professionals working with 5G NR, NTN, 5G-Advanced, satellite communications, IoT, and the future 6G ecosystem.
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