6G standardization – an overview of timeline and high-level technology principles

6G is entering the pre-standardization phase.

At the end of 2023, 3GPP committed to the development of the sixth-generation mobile system. To solidify the commitment, a timeline for 6G standardization was decided at the March 2024 3GPP meetings in Maastricht, the Netherlands. Ericsson is ready to support 3GPP’s ambition to be the main specification body for 6G, as it has been for earlier generations. There will also be other industry standardization fora, like the Open Radio Access Network (O-RAN) Alliance involved in developing parts of the 6G networks, however, this blog post is focused on the work in 3GPP.

We will outline the 3GPP agreed timeline, its correlation with the International Telecommunication Union (ITU) and highlight key principles for 6G.

ITU key points and timelines

ITU plays a key role in standardization – defining the criteria for a system to be classified as an International Mobile Telecommunications (IMT) technology. IMT classification is important as it provides access to a large set of frequency bands that are globally or regionally recognized as IMT bands. This is an important step on the way to establishing a global commercial ecosystem for 6G.

ITU designates 6G as IMT-2030, with 5G referred to as IMT-2020, 3G as IMT-2000, and 4G as IMT Advanced.

In ITU, the work on IMT-2030 is divided into a set of different tasks, some of which have already been completed and some are about to begin. The below illustration outlines a high-level overview of the different steps ITU will take to define IMT-2030.

Figure 1: ITU timeline for IMT-2030

The first step was the completion of the two deliverables, “The Future Technology Trends”¹ and the “Framework for IMT-2030 and Beyond”².

From 2024 to the end of 2026, ITU will work on defining technical performance requirements and the corresponding performance evaluation methodologies for IMT-2030. The requirements will be functional, that is, the system should support a certain function, or quantitative, where under given conditions the system should be able to deliver, for example, a certain spectral efficiency, latency, and positioning accuracy.

After the work on requirements is done, the process of submitting technologies for IMT-2030 starts in 2027 and runs until the beginning of 2029. 3GPP will for this purpose submit self-evaluations of 6G to ITU by end of 2028 or early 2029.

The final step which involves ITU’s decision to designate a technology as IMT-2030 is estimated to be completed by 2030. Later, it will be possible to update the submission during early 2030 with the latest versions of the specifications. This timeline will allow commercial 6G deployments to see the light of day in 2030.

Timeframe of 3GPP evolution to 6G

As of 2023, 3GPP has committed to developing 6G specifications³. To solidify the commitment, during the meetings in March, 2024, 3GPP took a large step by agreeing a timeline for 6G⁵. Here, we will look more closely at the time plan for this project and provide a high-level breakdown of the various tasks involved in such a large project.

The 3GPP timing together with additional Ericsson’s views on it is illustrated in Figure 2.

Figure 2: 3GPP timing

3GPP work is typically done in releases and the work on Release 19 started at the beginning of 2024⁴. At the end of each release, 3GPP updates its specifications to reflect the work done during the release.

For a new G, the work is so extensive that it spans multiple releases. 5G started with Release 14 with the first specifications finalized in Release 15. 6G work in 3GPP will start in 2024 during Release 19 with requirement related work and the first specifications should, according to Ericsson's view, be completed at the end of 2028 in Release 21. The 3GPP endorsed timeline enables initial commercial system to be available in the market by 2030 and is aligned with the ITU timeline.

It is noteworthy to mention that while 3GPP is developing 6G, the evolution of 5G Advanced will continue in 3GPP for several releases, developing new technology that will serve the global market until 2030 and beyond. Apart from the continued evolution of 5G Advanced in the market, this will also ensure a smooth transition to 6G.

Let us delve deeper into the different phases of the 3GPP work on 6G and highlight key milestones and relations to the ITU work described earlier.

Somewhat simplified, the work is on high-level split into four different phases:

• a use case and requirements study during Release 19 and 20, followed by
• a technical study in Release 20, spanning into the beginning of Release 21, and finally
• a 6G work item and a 6G self-evaluation study in Release 21

6G requirement study

The work on requirements in 3GPP will kick off in May 2024, to start defining the 6G service requirements. Market representatives will present their views on novel aspects to be considered for 6G, and 3GPP will discuss the scope of the service requirement study.

The study is targeted to be approved in September 2024.

Typical service level requirements describe, at a very high level, the specific requirements imposed by a particular functionality on the whole communication system. User Equipment (UE), Radio Access Network (RAN) equipment, core network, security architecture, operation and maintenance, and so on, are all considered. Since 6G is a new system, the study will include both new use cases and enhancements of functionality already supported in 5G.

There will also be work specifically on requirements on the UE and RAN side. These requirements are in part more detailed. One task is to handle the ITU requirements. Initial discussions will start in September 2024 and with the scope of the work more solidified by December 2024, a study item will be agreed. Most of the ITU related requirement work will be completed by June 2025.

The second part of the requirement work is to address any high-level requirements coming from commercial considerations that are not captured by the ITU requirements. An example of one such requirement is the efficient migration from 5G to 6G. The study item addressing these requirements will start from June 2025 and end in June 2026.

In summary, this yields a RAN-level requirement study phase starting from September 2024 and finalizing in June 2026.

6G Technical Study and Work Item

The main task for 3GPP will be to design the 6G system. The technical work in the working groups will start in Q3 2025. The design of the 6G system will be done in two phases over two releases.

First is a study where different techniques are studied. The second phase will go into detailed design, culminating in the fully implementable 6G specifications in Release 21. The study will begin in Q3 2025 and will be 21 months long. This will go in parallel with work on 5G Advanced evolution during Release 20, which will have a duration of 18 months only.

During the technical study and the work on requirements, the 3GPP community will get a clearer picture of the time needed to finalize 6G. Considering these findings and the commercial needs that may develop, 3GPP will by latest June 2026 agree when the Release 21 work item will be finalized, creating the first versions of the 6G specifications.

That said, to enable commercial 6G systems to be available by 2030, Ericsson believes that the Release 21 work item should be finalized by end of 2028.

High level principles for 6G

With the timeline decided, the focus of the discussion will shift to the content of the study item and the actual 6G design. Although the term “6G” is broad and may encompass more than connectivity services, several key principles can be envisioned.

First, 6G should be a global standard, supporting not only new, not-yet-foreseen use cases, but, more importantly, massive-scale adoption of use cases starting to emerge in 5G such as XR. Key verticals such as low-power wide area (LPWA) IoT, fixed wireless access (FWA), non-terrestrial networks (NTN), and dependable and time-critical communication should be addressed from the start. In earlier generations, support for these scenarios was added at a later stage, sometimes with overly complex solutions, implying limited uptake in practice.

Spectrum-wise, 6G should support operation in a wide range of spectrum allocations including FR1, FR2, and the cm-wave range. Highly efficient multi-RAT spectrum sharing (MRSS) between 5G and 6G is essential to provide wide area 6G coverage and MRSS should be an integrated part of the 6G design from the start. Fortunately, the ultra-lean design of 5G implies that 5G-6G sharing can be made very efficient with an overhead of a few percent at most (unlike the 4G-5G sharing which is inherently less efficient given the 4G design with cell-specific reference signals).

Furthermore, the transition from 5G to 6G must be smooth with a single migration path. A key learning from 5G is to avoid a plethora of architectural options fragmenting the market and slowing down the adoption of the new technology⁶. This implies that:

• 6G RAN should connect to an evolution of the 5G core network. The 5GC is yet to be rolled out by many operators and its architecture is flexible and can easily be extended to handle new 6G features. Building upon the well-established baseline of the 5G core network enables a smooth and cost-efficient introduction of the 6G RAN and other 6G features.
• 6G should support stand-alone operation only; at each point in time the device is connected to either 5G or 6G. Although dual connectivity across Gs initially may look like a good way to aggregate spectrum resources, this is not the case, and in reality, dual connectivity results in poor performance and typically all the traffic traversing on one of the legs only. MRSS is the preferred migration path.
• 6G should include open interfaces for a healthy ecosystem. Hence, standardization efforts should be focused on key interfaces where multi-vendor interoperability is valuable from a business perspective and technically feasible. This (obviously) includes the RAN-CN interface and the air interface itself, but also the next-generation lower-layer split and an interface between RAN nodes for mobility.

Observability is critical for enabling widespread usage of AI/ML and automation in general. This must be accounted for from the start, for example by specifying the necessary device-side measurements and reports.

Finally, energy performance is one of the most important areas to keep in mind. On the network side, the ultra-lean paradigm of 5G should be extended in the spatial and frequency domains by separating the design of idle and connected modes. To ensure a long battery life on the device, features such as wake-up signals should be included in the baseline design.

Figure 3: Simplified 6G architecture.

Summary of the 6G timeline

Work on defining IMT-2030 and beyond has been ongoing in ITU for some years already and will be more concrete in 2024 with the start of the work on the technical performance requirements.

In 2023, 3GPP initiated a 6G activity by announcing a commitment to develop 6G specifications and starting its own requirement work during 2024. In the approved timeline for the 6G work, the plan is to start development of 6G technology in mid-2025 with a 21-month study item which will analyze the technology options. In June 2026 at the latest, 3GPP will decide the duration of Release 21 work item and hence the date for the availability of the first versions of 6G specifications. Ericsson believes the 6G specifications should be ready by end of 2028. This will allow for the introduction of the first commercial 6G systems to the market by 2030.

More reading

Read more about 6G

Read the blog post Six talking points for architecting the next wireless generation

More about 5G Advanced from Ericsson

Read the blog post The next wave of advanced 5G – 3GPP Release 19

Read the article in Ericsson Technology Review 6G network architecture – a proposal for early alignment