5G&6G
R&D

5G Overview (IMT-2020)

Consumer demands are shaping the development of mobile broadband services. Anticipated increases in traffic (estimated as 10-100 times over the period 2020 – 2030), growth in the number of devices and services, as well as demand for enhanced affordability and user experience will all require innovative solutions. The number of connected devices on the Internet is projected to reach 50 billion any time from 2025 onwards.
The fifth generation of mobile technologies - 5G - connects people, things, data, applications, transport systems and cities in smart networked communication environments. The networks transport a huge amount of data much faster, reliably connect an extremely large number of devices and process very high volumes of data with minimal delay.
5G technologies support applications such as smart homes and buildings, smart cities, 3D video, work and play in the cloud, remote medical services, virtual and augmented reality, and massive machine-to-machine communications for industry automation. Legacy 3G and 4G networks face challenges in supporting these services.
Although the business cases and scope of use present challenges, these new functionalities and new services necessitate a new way of deploying advanced mobile services, as well as new approaches in making 5G technologies work together in industrial settings by machine-to-machine communications, Internet of Things (IoT) or with connected vehicles.
ITU plays a leading role in managing the radio spectrum and developing globally applicable standards for IMT-2020. ITU is working towards providing stable international regulations, sufficient spectrum and suitable standards for IMT-2020 and the core network to enable successful 5G deployments at the regional and international levels.
The first edition of the IMT-2020 specifications, the name used in ITU for the standards of 5G, has been published in February 2021 (ITU-R M.2150). Since then, more than 300 commercial launches across the world and more than 2700 announced devices (at least 50% already commercially available) can be noted.
Initially, three technologies were approved as meeting IMT-2020 specifications: 3GPP 5G-SRIT, 3GPP 5G-RIT, and 5Gi.
Two, provided by the Third Generation Partnership Project (3GPP), represent the well-known “standalone- (SA)", 3GPP 5G-RIT, and “non-standalone- (NSA)", 3GPP 5G-SRIT, 5G deployment models, of which the 5G-SA has a completely new RAN- and core-architecture, without the necessity of an underlying 4G-network.
5Gi provided by Telecommunications Standards Development Society India (TSDSI) is an updated version of 3GPP 5G-RIT, designed mainly to improve rural coverage.
In February 2022, a fourth technology called DECT 5G-SRIT was designated as meeting the standard. Due to the non-cellular and autonomous, decentralized technology, it supports a range of use-cases, from wireless telephony and audio streaming to industrial Internet of Things (IoT) applications, particularly in smart cities.

6G Overview (IMT-2030)

As the first result of the work on IMT-2030 (6G) which started back in late 2021, ITU-R developed a report on the “Future Technology Trends", which has been published as Report TU-R M.2516 in December 2022.
In December 2023, ITU published the framework for the development of standards and radio interface technologies for the sixth generation of mobile systems, popularly referred to as 6G. The details of the 6G framework are contained in Recommendation ITU-R M.2160 on the "IMT-2030 Framework" approved by the ITU Radiocommunication Assembly (RA-23) at its recent meeting in Dubai, United Arab Emirates.
The IMT-2030 Framework Recommendation classifies 6 “usage scenarios" – three extended from IMT-2020 and three new ones. It also identifies 15 capabilities for 6G technology - nine of those capabilities are derived and extended from existing IMT-2020 systems.
For the next phase of 6G development, companies and industry associations will submit proposals for the IMT-2030 Radio Interface Technology (RIT) for ITU-R consideration in early 2027. These submissions will then be evaluated against the agreed minimum requirements prepared by ITU's expert group on IMT systems (ITU-R Working Party 5D), with the prospect of getting a final set of 6G technology standards approved by 2030.
IMT-2030 is also expected to help address the need for increased environmental, social and economic sustainability, and also support the goals of the Paris Agreement of the United Nations Framework Convention on Climate Change.
While IMT-2020 (5G) already addressed initial considerations to accelerate the achievement of the 17 Sustainable Development Goals (SDGs) like energy consumption, IMT-2030 (6G) is expected to have dedicated requirements for the RIT-candidates to support the SDGs (lasting from affordable and clean energy to zero hunger).
At WRC-23, ITU Member states considered International Mobile Telecommunication (IMT) and mobile use of a range of mid and low band frequency ranges. The conference identified spectrum for IMT which will be crucial for expanding broadband connectivity.
At its first meeting in 2024, ITU-R approved a new Report ITU-R M.2541 about the “Technical feasibility of IMT in bands above 100 GHz", which includes information on propagation mechanisms and channel models, as well as newly developed technology enablers like active and passive components, antenna techniques, deployment architectures, and the results of simulations and performance tests. As such, it complements Report ITU-R M.2376 containing studies for the frequency ranges 6-100 GHz.

ITU-R Report M.2516, Future technology trends of terrestrial International Mobile Telecommunications systems towards 2030 and beyond, 2022.
ITU-R Recommendation M.2160, IMT-2030 Framework and overall objectives of the future development of IMT for 2030 and beyond, 2023.
ITU-R Report M.2541, Feasibility of IMT above 100 GHz, 2024.

5G 3GPP System overview

IntroductionThe Fifth Generation of Mobile Telephony, or 5G, or 5GS, is the system defined by 3GPP from Release 15, functionally frozen in June 2018 and fully specified by September 2019.3GPP defines not only the air interface but also all the protocols and network interfaces that enable the entire mobile system: call and session control, mobility management, service provisioning, etc. Thanks to this approach 3GPP networks can operate in an inter-vendor and inter-operator context.5G is defined in several phases. Release 15 specifies 5G phase 1, which introduces a new radio transmission technique and other key concepts such as an industry-grade reliability, an extended modularity, or a faster response time.All previous generations have been designed to be used by an ever wider audience, 5G is pushing out further – ready for use by all industry sectors and for time critical applications, such as autonomous driving.To offer these capacities, and more generally to improve the user experience, 5G makes use of a set of dedicated technologies, such as "Network Function Virtualization" and "Slicing" to increase the modularity, "EDGE computing" for faster response time, Non-Terrestrial Networks (NTN) / Satellite Communications for ubiquitous coverage, etc.
The road to a fifth generation3GPP plays a major part in the approximate once-every-decade generational progression since the first phase of mobile standards in the 1980s. Each generation has harvested improvements throughout the system, measured in 3GPP Releases – with the groups having recently starting progress on Rel-18 specifications.As the name suggests, 3GPP started work in 1998 on the third generation of mobile, using techniques and an evolutionary path that could be embraced by all regions. This Global convergence towards the 3GPP specifications has allowed fantastic market growth and an increasing level of assurance that broadband cellular - and now the internet-of-everything - can rely on a stable and future looking standardization platform.From an array of mobile systems for early generations, all operators are now offering 3GPP systems, with LTE (4G) delivered by over 800 operators, with 150 of them already offering 5G to their users (Source: GSAcom.com).
5G services5G improves on the 4G services over several axis:

Enhanced Mobile Broadband (eMBB): Higher data-rates are specified. For the downlink, up to 50 Mbps are offered for outdoor and 1 Gbps for indoor (5GLAN), with half of these values available for the uplink. A number of case studies have been under consideration, amongst them is aviation – where eMBB is helping deliver a bitrate of 1,2 Gbps to an airborne flight.
Critical Communications (CC) and Ultra Reliable and Low Latency Communications (URLLC): In some contexts, extremely high reliability is expected. For instance, for remote control of process automation, a reliability of 99,9999% is expected, with a user experienced data rate up to 100 Mbps and an end-to-end latency of 50 ms. This is provided in particular through the Edge Computing capability.
Massive Internet of Things (mIoT). Several scenarios require the 5G system to support very high traffic densities of devices. The Massive Internet of Things requirements include the operational aspects that apply to the wide range of IoT devices and services anticipated in the 5G timeframe.
Flexible network operations. These are a set of specificities offered by the 5G system, as detailed in the following sections. It covers aspects such as network slicing, network capability exposure, scalability, and diverse mobility, security, efficient content delivery, and migration and interworking.

More information on these axis is provided in:

Release 15 Description; Summary of Rel-15 Work Items (TR 21.915)
Service requirements for the 5G system (TS 22.261)
NR and NG-RAN Overall description; Stage-2 (TS 38.300).

This diversity of requirements, associated to the different categories of usage described above, enables the 5G system (5GS) to be useful to a new set of markets aka. "verticals", including: automotive, rail & maritime communications; transport and logistics; discrete automation; electricity distribution; public Safety; health and wellness; smart cities; media and entertainment.In addition to the new 5G-specific services, the 5G system supports almost all the 4G LTE ones [1 – 9] and mobility between a 5G core network and a 4G core network (EPC) is supported, with minimum impact on the user experience.
Overall architectureSchematically, the 5G system uses the same elements as the previous generations: a User Equipment (UE), itself composed of a Mobile Station and a USIM, the Radio Access Network (NG-RAN) and the Core Network (5GC).The main entity of the NG-RAN is the gNB, where "g" stands for "5G" and "NB" for "Node B", which is the name inherited from 3G onwards to refer to the radio transmitter. The radio interface is named "NR-Uu" for similar reasons, although with divergences: here, "5G" is indicated by "NR" (for "New Radio") and Uu is also a name inherited from previous generations. The gNB may be further split into a gNB-Central Unit (gNB-CU) and one or more gNB- Distributed Unit(s) (gNB-DU), linked by the F1 interface.The 5GC is here schematically represented by the AMF/UPF entity: the User Plane Function (UPF), handling the user data and, in the signalling plane, the Access and Mobility management Function (AMF) that accesses the UE and the (R)AN. Further entities of the 5GC are presented below. The reference point between the access and the core networks is called "NG". This reference point is constituted of several interfaces (mostly N2, N3), as shown below.The 5GC architecture relies on a "Service-Based Architecture" (SBA) framework, where the architecture elements are defined in terms of "Network Functions" (NFs) rather than by "traditional" Network Entities. Via interfaces of a common framework, any given NF offers its services to all the other authorized NFs and/or to any "consumers" that are permitted to make use of these provided services. Such an SBA approach offers modularity and reusability.The User Plane, i.e. the Network Functions (NFs) and elements involved in the transport of user data, is shown at the bottom level, whereas the upper part of the figure shows all the essential NFs within the signalling plane. In this first approach, the following NFs are shown:

The four entities already introduced, i.e.: the UE, the NG-RAN or (R)AN, the UPF and the AMF
The (external) Data Network (DN), mostly in the User Plane
The Application Function (AF), controlling the application(s) (with possible involvement also in the user plane)
The Session Management Function (SMF), that handles the calls and sessions, and contacts the UPF accordingly
The Unified Data Management (UDM), functionally similar to 3G and 4G's HSS (and 2G's HLR)
The Policy Control Function (PCF), that controls that the user data traffic does not exceed the negotiated bearer(s) capacities
The Network Repository Function (NRF), which "controls" the other NFs by providing support for NF register, deregister and update service to NF and their services.
The security-related NFs: Network Exposure Function (NEF), Authentication Server Function (AUSF), Security Anchor Functionality (SEAF) – see TechGuide "Security in 5G"
The Network Slice Selection Function (NSSF) – see TechGuide "Slicing in 5G"

The charging framework migrated from the Diameter based Off- and Online charging to converged charging service with Service Based Interface (SBI) as defined in TS 32.240, for Operators to be able to monetize the various set of 5GS features and services.5G Protocol stacksA protocol stack is defined e.g. in TS 23.501 for communications between several of these NFs, and secondary ones, not presented in the figure above. Here, we highlight some of the main ones:

Control plane: the UE-to-AMF and UE-to-SMF protocol stack
NAS-SM: it supports the handling of Session Management between the UE and the SMF. It supports user plane PDU Session Establishment, modification and release. It is transferred via the AMF, and transparent to the AMF. It is defined in ‘Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3’ (TS 24.501).
NAS-MM: it supports registration management functionality, connection management functionality and user plane connection activation and deactivation. It is also responsible of ciphering and integrity protection of NAS signalling. 5G NAS protocol is defined in TS 24.501.
5G-AN Protocol layer: This set of protocols/layers depends on the 5G-AN. In the case of NG-RAN, the radio protocol between the UE and the NG-RAN node (eNodeB or gNodeB) is specified in the E-UTRA & E-UTRAN; ‘Overall description; Stage 2’ (TS 36.300) and the NR ‘Overall description; Stage-2’ in TS 38.300. In the case of non-3GPP access, see clause 8.2.4.
NG Application Protocol (NG-AP): Application Layer Protocol between the 5G-AN node and the AMF. NG-AP is defined in TS 38.413.
Stream Control Transmission Protocol (SCTP): This protocol guarantees delivery of signalling messages between AMF and 5G-AN node (N2). SCTP is defined in ietf RFC 4960.
Note that there is also a direct communication between 5G-AN and SMF, called N2 SM information: this is the subset of NG-AP information (not shown on the figure) that the AMF transparently relays between the 5G-AN and the SMF, and is included in the NG-AP messages and the N11 related messages.
User plane: the UE-to-AMF and UE-to-SMF protocol stack
PDU layer: This layer corresponds to the PDU carried between the UE and the DN over the PDU Session. When the PDU Session Type is IPv4 or IPv6 or IPv4v6, it corresponds to IPv4 packets or IPv6 packets or both of them; When the PDU Session Type is Ethernet, it corresponds to Ethernet frames; etc.
GPRS Tunnelling Protocol for the user plane (GTP U): This protocol supports tunnelling user data over N3 (i.e. between the 5G-AN node and the UPF) and N9 (i.e. between different UPFs of the 5GC) in the backbone network, details see TS 29.281. GTP shall encapsulate all end user PDUs. It provides encapsulation on a per PDU Session level. This layer carries also the marking associated with a QoS Flow defined in clause 5.7. This protocol is also used on N4 interface as defined in TS 29.244.
5G-AN protocol stack: This set of protocols/layers depends on the AN. When the 5G-AN is a 3GPP NG-RAN, these protocols/layers are defined in TS 38.401. The radio protocol between the UE and the 5G-AN node (eNodeB or gNodeB) is specified in TS 36.300 and TS 38.300. L2 is also called the "Data Link Layer" and the L1 is the "Physical Layer".
UDP/IP: These are the backbone network protocols.

The 5G radio interface5G's radio technology is called NR (for New Radio). It is specified in TS 38.300 "NR; NR and NG-RAN Overall description; Stage-2".For layer 1: for the downlink (DL), i.e. network to UE, NR uses OFDM with Cyclic Prefix (CP) (similar to LTE). For the uplink (UL), i.e. UE to network, OFDM can also be used, as well as DFT-s-OFDM (OFDM with Discrete Fourier Transform precoding). DFT-s-OFDM improves UL coverage but it has lower peak-to-average power ratio (PAPR) and is limited to single-layer transmission only.Some key characteristics of 5G layer 1 is that it spreads over multiple frequency ranges, to enable deployment in frequencies on a per-country or per-region basis. The carriers are from 400 MHz up to 100 GHz, but the licensed bands are from 600 MHz up to 39 GHz. These frequencies are re-farmed analogue TV (UHF) bands and some satellites systems, without interference since used in different locations.
For terrestrial, 3 main ranges of frequencies are identified:

Up to 1 GHz: with its better propagation characteristics, this set is intended to cover large areas, typically for rural deployment. The maximum bandwidth for one carrier is 100 MHz.
From 1 to 6 GHz: this intermediate range is for 5G deployment in a urban or sub-urban context. Here too, the maximum bandwidth is 100 MHz.
Higher than 6 GHz: with its poorer propagation but higher bandwidth to the user (maximum bandwidth of 400 MHz), this range is meant for dense urban environment ("hot-spot" type of coverage).

More high-level details of the 5G NR, including the layer 1, are provided in the Summary of Rel-15 Work Items: TR 21.915.
The "Non-Stand Alone" (NSA) versus the "Stand-Alone" (SA) architectureTwo deployment options are defined for 5G:

the "Non-Stand Alone" (NSA) architecture, where the 5G Radio Access Network (AN) and its New Radio (NR) interface is used in conjunction with the existing LTE and EPC infrastructure Core Network (respectively 4G Radio and 4G Core), thus making the NR technology available without network replacement. In this configuration, only the 4G services are supported, but they enjoy the capacities offered by the 5G New Radio (lower latency, etc). The NSA is also known as "E-UTRA-NR Dual Connectivity (EN-DC)" or "Architecture Option 3". See also the clause on EDCE5.
the "Stand-Alone" (SA) architecture, where the NR is connected to the 5G CN. Only in this configuration, the full set of 5G Phase 1 services are supported.

The NSA architecture can be seen as a temporary step towards a "full 5G" deployment, where the 5G Access Network is connected to the 4G Core Network. In the NSA architecture, the (5G) NR base station (logical node "en-gNB") connects to the (4G) LTE base station (logical node "eNB") via the X2 interface. The X2 interface was introduced prior to Release 15 to connect two eNBs. In Release 15, it also supports connecting an eNB and en-gNB to provide NSA.The NSA offers dual connectivity, via both the 4G AN (E-UTRA) and the 5G AN (NR). It is thus also called "EN-DC", for "E-UTRAN and NR Dual Connectivity". In EN-DC, the 4G's eNB is the Master Node (MN) while the 5G's en-gNB is the Secondary Node (SN). This is explained in detail on the dedicated section on NSA of this document.The SA architecture can be seen as the "full 5G deployment", not needing any part of a 4G network to operate.The NR base stations (logical node "gNB") connect with each other via the Xn interface, and the Access Network (called the "NG-RAN for SA architecture") connects to the 5GC network using the NG interface.
Some specificities of the 5G networkThe rest of this section refers to the 5G SA architecture, with the NSA being addressed in a later section.More than a new radio interface, the 5G network introduces a number of key new technologies. Some of them are briefly introduced here:

Network Slicing: This is the ability to deploy and use simultaneously different CNs, each one specialised in the provisioning of a given set of services and/or a given set of subscribers. For instance, one slice can support the "usual" network operator’s subscribers, another slice might be dedicated to support the subscribers of a virtual operator, a third one can handle a specific service, like tracking of containers via M2M, etc.
Network Function Virtualization: All the Network Functions communicate through a common interface and so can be located anywhere. This allows for much greater flexibility in the network deployment. Maintenance is also greatly simplified, as a temporary NF can be easily established.
EDGE computing: Some computational power is introduced as "physically close" to the end-user as possible. Indeed, some applications such are virtual reality, factories of the future or autonomous driving, are very demanding in terms of the propagation's/network's response time. To reduce this time, some "local replications” of a main server are introduced closer to the end-user.

Going furtherThe 5G system is described in over a thousand 3GPP Technical Reports (TRs) and Technical Specifications (TSs).

3GPP TR 21.915 Release 15 Description; Summary of Rel-15 Work Items
3GPP TR 21.916 Release 16 Description; Summary of Rel-16 Work Items
3GPP TR 21.917 Release 17 Description; Summary of Rel-17 Work Items
3GPP TR 21.918 Release 18 Description; Summary of Rel-18 Work Items

3GPP 6G specifications3GPP announced in Dec. 2023 that will develop the next generation of global communications specifications. Based on its success over several technology generations — from 3G to 5G — 3GPP is uniquely positioned to develop the standard for the sixth generation of mobile systems or "6G". The organization's consensus-based process delivers the critical technical specifications that provide a complete system description for the mobile networks that billions of users depend on.3GPP is currently at work on Release 18 and will soon begin development of Release 19 of its specifications, which relate to 5G-Advanced. However, delivery of a new mobile generation is a multi-year process. That is why the work for the 6G specifications is being planned well in advance. 5G brought increased interest in 3GPP, with the organization growing to meet the demands of more sectors and new services. Further growth may be expected as the needs of 6G use cases are considered in the standards development process.Since its inception, 3GPP has successfully delivered on the promise of cellular communications. The Organizational Partners in the project now stand ready to embark on the planning for the next generation, 6G.
The Work Plan provides details of the co-operation between all the 3GPP TSGs and WGs on reaching common targets. These targets are "Features" that add new or enhanced functionality to the existing system. Feature development is based around 3GPP Releases. The work plan is driven by the estimated freeze date of current and future Releases and the functional content of each Release. It is possible that features may span more than one Release.These features are divided into building blocks and work tasks, which lead to the production of Technical Specifications (TS) or Reports (TR).

6G Standardization timeline

6G standardization is getting off the ground in 2024. In this blog post, you will learn the latest about the 6G standardization timeline in 3GPP and ITU, and the key principles we envision for the actual 6G design.6G is entering the pre-standardization phase in march 2024.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 timelinesITU 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.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 6GAs 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.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 studyThe 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 ItemThe 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 6GWith 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.

SummaryWork 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. It is believed 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.

Role of ITU-R

ITU-R plays a key role in 6G standardization. Specifically, the role of ITU-R includes three main phases:

phase 1) build a vision of IMT-2030 (2020–2023)
phase 2) define performance/service requirements and evaluation methodology/criteria (2024–2026)
phase 3) evaluate candidate RITs and select the IMT-2030 compliant (i.e., 6G) ones by the end of 2030 (2027–2030)

Role of 3GPP

3GPP is a large consortium that develops international standards for mobile telecommunication networks. 3GPP cellular standards are developed through Releases, each of which comprises a major package of new technological features for mobile networks, covering the core network, radio access, terminal, and service capabilities. In each Release, new technological features are studied and defined in Technical Reports (TRs) and Technical Specifications (TSs). Specifically, TRs and TSs are the outputs of study items and work items, respectively.

A study item is an exploratory phase to examine the potential and feasibility of new features and technologies, with no commitment to immediate standardization.
A work item is a phase to develop exact specifications for new features and technologies, with the
intention of producing formal standards.

When 5G evolution approaches its limits, the standardization efforts begin to shift toward 6G. The 6G standardization process is estimated to begin in 2025.

If Release 19 will be completed by mid-2025, as planned, the preparation of Release 20 will begin in July 2025. It is planned that Release 20 will begin the 6G standardization process by being the first Release to study 6G features. Assuming the average 18 months preparation time for a Release, Release 20 is anticipated to be finalized by the end of 2026.
The preparation of Release 21 to begin in early 2027. Release 21 is expected to be the first Release to define 6G technologies. Thus, being the first official 6G standard. Most likely Release 21 will be included in the 3GPP submission to ITU-R as a potential 6G radio interface candidate to meet the IMT-2030 requirements.

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