Latest 3GPP standards-development work includes new classes of HPUE, progress on mission-critical services

Highlights

The 3GPP Plenary meetings took place March 18-22, 2024, in Maastricht, Netherlands. 3GPP Radio Access Network (RAN) and Core Terminal (CT) groups continued to focus on completing the work for Release 18 (R18). The specifications are functionally frozen (no new features will be added) and only minor exceptions remain. The specifications remain on track for completion by June 2024. The RAN group reported that initial work has started for Release 19 (R19). The 3GPP Service and System Aspects (SA) group reported activities continued to focus on R19 as well as planning for the 6G workshop in May 2025.

During the joint cross-Technical Specifications Groups (TSG) (e.g. RAN, SA, and CT) meeting, it was indicated that the freeze date for 6G technology standards likely will not be finalized earlier than March 2029. The functional freeze date for R19 is currently on track, and the final completion date is planned for December 2025.

The following TSG reports include details on each of the Plenary TSG meetings focused on progressing features important to public safety. The First Responder Network Authority (FirstNet Authority) and government agencies of other nations continue to represent public-safety interests.

The Radio Access Network TSG Plenary

There were more than 425 face-to-face attendees at the TSG RAN Plenary meeting. The RAN plenary is responsible for defining the requirements, functions, and interfaces of the 3GPP radio access network.

RAN1 working group—responsible for the specification of the physical layer of the radio interfaces—reported the kickoff of the R19 study items. These items included the study on solutions for Ambient IoT (Internet of Things) for New Radio (NR, a.k.a., 5G) and the study on channel modeling for Integrated Sensing and Communication (ISAC) for NR.

The Ambient IoT feature is designed to let wireless sensors derive energy from solar and/or wind power, eliminating the need for frequent change of batteries. The ISAC allows the network to collect data on the range, velocity, position, size and materials of objects in coverage areas to meet the situational-awareness needs of public safety.

The group also reported the kick-off for the next generation of work on NR Non-Terrestrial Networks (NTN), also known as satellites. This work addresses performance optimization of terminals, including the capacity on uplink, the notification of the service area for a broadcast service, and the support for an NTN architecture with 5G system functions on board the NTN platform (i.e. regenerative payloads).

RAN2 working group—responsible for defining the Radio Interface architecture and protocols—reported the completion of all R18 features, including NTN-IoT (Internet of Things) enhancements and the NR support for Uncrewed Aerial Vehicles (UAV).

The report also included an update about completing the enhanced support for Reduced Capacity (RedCap) NR devices, and Network-controlled Repeaters (NCR). The NCR feature provides improved extension of network coverage on all spectrum bands compared to the more inefficient traditional repeaters that are currently available for public safety.

The group also reported on the completion of Dynamic Spectrum Sharing (DSS), a feature that lets multiple radio-access technologies share the same spectrum.

Additionally, the group reported on the completion of NR Positioning with higher positioning accuracy. This is achieved using two techniques: one to take advantage of the rich 5G spectrum to increase the bandwidth for the transmission and reception of the positioning reference signals, and the other is to use the NR carrier phase measurements.

RAN4 working group is responsible for work on the Radio Frequency (RF) aspects, including performing simulations and deriving the minimum requirements for transmission and reception parameters for user-equipment devices.

The group reported on the completion of specifications for Power Class 2 (PC2 = 400 milliwatts) high-powered user equipment (HPUE) for LTE Band 14 (B14) and NR band 14 (n14).

As reported in previous blogs, the PC2 operates at lower power than Power Class 1 (1.3 watts) HPUE and will be more flexible to use in traditional form factors, including hotspot routers and possible use as a regular User Equipment (UE). As a reference, the typical smartphone used today is PC3 (200 milliwatts).

The working group also added high-power-class UEs for NTN use. These include PC1 and PC1.5 (PC 1.5 is twice the power as that of PC2). These newly defined power classes increase uplink transmit power, enabling devices to better access satellites, thus enhancing coverage for public safety.

RAN5 working group—responsible for the development of UE conformance test specifications—typically works one to two releases behind the other working groups.

The group reported that Conformance Test Aspects – protocol enhancements for Mission Critical (MC) Services, as defined in R16 (MCPTT, MCVideo, and MCData), is 67% complete and expected to be 100% complete by September 2024.

The other significant public-safety related UE conformance test specifications include NR Sidelink single-hop UE to Network relay (25% completed) and NR positioning enhancements, as defined in R17 (38% completed).

Finally, it was also confirmed that the functional freeze date for R19 work in TSG RAN is on track, and the final completion date is scheduled for December 2025.

The Service and System Aspects TSG Plenary

More than 270 people attended the TSG SA Plenary meeting in person. TSG SA is responsible for the overall architecture and service capabilities of 3GPP-based systems.

Since the December plenary, 3GPP SA work has focused primarily on progressing R19 features. Time was also spent planning for R20 and beyond, as 6G technology is now becoming more of a focus in 3GPP.

As discussed in previous blogs, the SA1 typically works one release ahead of the other 3GPP working groups. For public safety, 3GPP SA1 completed all R19 work at the December 2023 meeting and is currently working on R20, which will be divided into two activity paths. The first path will focus on 5G-Advanced feature updates and enhancements, and the second path will look at studies for 6G.

Initial discussions of R20 features included enhancements of mission-critical work for railways and satellite access, both of which have value for public safety. The FirstNet Authority plans to define and introduce several new requirements and use cases to meet public-safety needs for these services.

The SA1 working group—responsible for studying new and enhanced services, features, and capabilities—continues to plan for 6G in R20. The group agreed to plan for an International Mobile Telecommunications (IMT) 2030 workshop in May 2024.

The workshop will begin looking at the work underway by the 3GPP market representative partners (groups representing wireless-communication market needs), and other invitees from global research and trade organizations interested in 6G. This workshop will focus only on presentations from outside partners to provide guidance to 3GPP for 6G technology direction.

The SA2 working group—responsible for the 5G System and Evolved Packet System (EPS) Architectures—reported steady progress for R19 architectural studies on high-priority features for public safety.

These studies included one of the top priority features for the FirstNet Authority, which are the Proximity Services (ProSe) enhancements. This includes the support for multi-hop UE-to-Network relay (MU2N) and multi-hop UE-to-UE relay (MU2U). These enhancements will increase communications coverage and throughput in weak and off-network areas. This work progressed to 45% completion since the last meeting in December 2023.

Other studies for public-safety high-priority features reached 40% average completion. These features include enhancements to the vehicle-mounted relay to include backhaul support over NTN, Femtocell enhancements, Ambient IoT, artificial intelligence, and machine learning; and a phase 3 for UAVs that will improve detection and avoidance capabilities, as well as improved communications.

The SA3 working group—responsible for 5G Security Aspects—continues to make progress on enabling the 5G system to support use of cryptographic algorithms with 256-bit key sizes. At the TSG SA plenary meeting, specifications defining a portion of these 256-bit algorithms were approved.

SA3 also approved a new security study for R19 to address enhancements for proximity services. This proximity-services-focused work aims to evaluate and address security issues introduced with the new MU2N and MU2U capabilities being defined by 3GPP.

The SA6 working group develops the architectures for most MC features. The working group reported solid progress for R19 studies on high-priority features for public safety. The current R19 studies for the MC architecture have progressed to 40% completion.

The FirstNet Authority is planning additions to this study to support MC services over UE-to-UE single-hop relay. As you may recall, the single-hop relay was completed in R18. The feature on sharing of administrative configuration between MC service systems is being designed to let different MC organizations share information and allow easier migration of users. This work is reported at 90% completion.

The study enhancements for application enablement over satellite has shown progress. This study evaluation scope includes the impact of MC services support over satellite communications.

The Core Network and Terminals (CT) TSG Plenary

There were more than 200 in-person attendees at the TSG CT Plenary meeting. The CT TSG covers the protocol details that follow the requirements and architectural work performed in the SA TSG.

CT Plenary activities focused on finalizing R18 work. Much of the R18 work has been completed as scheduled, but with some exceptions, which is common in 3GPP. R18 work with exceptions include mission-critical push-to-talk (MCPTT), ProSe, MC services over 5G broadcast (5MBS), and ad-hoc communications.

All activities showed steady progress. Both mission critical over ProSe and 5MBS are complete and MCPTT and ad hoc communications are at 90% and 85% completion, respectively, and should be completed in the next quarter.

Further information on the 3GPP’s work and organization can be found at: www.3gpp.org.

Dean Prochaska is the senior director of standards for the First Responder Network Authority (FirstNet Authority). Contributors to the article include FirstNet Authority Senior Standards Engineers Jeff Cichonski, Ihab Guirguis, Satish Jha, Mark Lipford, and Eshwar Pittampalli.