3GPP 6G Standardization Roadmap: From Release 21 to the Future

Introduction

The 3rd Generation Partnership Project (3GPP) has been the architect of every cellular standard since 3G. Its standardization process, built on consensus among hundreds of member companies and research institutions, determines the technical specifications that billions of devices worldwide must comply with. As 6G development accelerates, understanding 3GPP's standardization roadmap is essential for anyone seeking to comprehend the future of mobile communication.

Current Status: The Bridge from 5G to 6G

3GPP's current work is organized around 5G-Advanced, spanning Releases 18, 19, and 20. These releases serve as critical stepping stones toward 6G by introducing foundational technologies:

• Release 18 (2024): AI/ML for the air interface, expanded MIMO, sidelink enhancements, and network energy savings
• Release 19 (2025-2026): Advanced AI/ML integration, ISAC study items, ambient IoT, and enhanced NTN (non-terrestrial networks)
• Release 20 (2027): Expected to be the final 5G-Advanced release, incorporating mature versions of ISAC, AI-native air interface elements, and sub-THz study results

The 6G Standardization Timeline

Based on 3GPP's historical cadence and current planning discussions, the 6G standardization timeline is expected to unfold as follows:

2025-2027: Study Phase. 3GPP conducts technology studies and requirements analysis. Working groups evaluate candidate technologies, conduct simulations, and develop channel models for new frequency bands. This phase defines what 6G could be.

2028-2029: Specification Phase (Release 21). The first 6G specifications are developed. Release 21 is expected to define the core 6G architecture, new air interface, and initial frequency band specifications. This phase determines what 6G will be.

2030-2031: Enhancement Phase (Releases 22-23). Subsequent releases refine and extend the initial 6G specifications, adding advanced features and optimizations based on early implementation experience and field trial results.

2030+: Commercial Deployment. Initial commercial 6G networks are expected to launch, beginning the deployment cycle.

Key Study Items for 6G

Several critical study items will shape 6G specifications:

New Air Interface: While 5G NR (New Radio) has been remarkably successful, 6G may introduce a fundamentally new air interface designed for THz frequencies, semantic communication, and AI-native operation. The question of whether 6G will evolve NR or introduce an entirely new waveform is one of the most significant open debates.

AI/ML Framework: Standardizing how AI models are trained, distributed, and executed within the network architecture. This includes model interchange formats, performance benchmarks, and interfaces between AI components and traditional network functions.

ISAC Specifications: Defining the waveforms, protocols, and interfaces for integrated sensing and communication, including coexistence rules with radar and other sensing systems.

Sub-THz and THz Bands: Channel models, deployment scenarios, and equipment specifications for frequencies above 100 GHz, building on research being coordinated with the ITU-R.

Industry Dynamics

6G standardization is influenced by intense geopolitical and commercial competition. Chinese companies (Huawei, ZTE, CATT) have filed the most 6G-related contributions to 3GPP working groups. European companies (Nokia, Ericsson) maintain strong positions in architectural design. Korean (Samsung) and Japanese (NTT) players are making significant contributions in THz and AI technologies. US influence comes primarily through chipmakers (Qualcomm, Intel) and hyperscalers (Google, Microsoft, NVIDIA).

Conclusion

3GPP's 6G standardization process will determine the technical foundations of next-generation mobile communication. While the timeline is structured and predictable, the outcome of key technical debates — new air interface design, AI standardization, and spectrum utilization — will shape an industry worth trillions of dollars. Stakeholders who engage actively in the standardization process today will define the communication systems of the 2030s.