This blog is a repost from IWCE’s Urgent Communications, originally published on April 13, 2023.

This blog post is part of the "Tech Talk" series focused on the First Responder Network Authority’s (FirstNet Authority) standards development activities to support public safety. This post recaps discussions linked to public safety and other related topics from the 3GPP Plenary meetings that were conducted in March 2023. The FirstNet Authority represented public safety interests at the Plenary meetings.

Highlights

The latest set of 3GPP Plenary meetings concluded on March 24, 2023, in Rotterdam, Netherlands. The meetings focused on the feature progress and schedule for Release 18 (R18) and included the initial discussions of Release 19 (R19) planning. The remaining stage 2 architectural work in R18 is advancing well and is expected to complete in June 2023, as scheduled, allowing the R18 stage 3 protocol work to proceed.

The FirstNet Authority took part in the R19 planning discussions to ensure an adequate development cycle for needed features. The Technical Specification Group (TSG) reports below highlight progress on R18 features of interest for public safety and provide a small peek at some expected R19 features.

A preliminary view of the completion date for R19 is December 2025. Two R19 planning workshops will be held during the upcoming June 2023 plenary meetings to provide clarity on R19 content and schedule with further fine tuning of the content until December 2023.

As a reminder, the work in a 3GPP release feature is typically done as a study phase first, followed by a normative phase to create product standards. The study phase is coordinated by study item descriptions (SIDs) for each feature, and the normative phase is coordinated by work item descriptions (WIDs). In general, the reader will note in the TSG reports below that the stage 2 architecture work on the R18 features is progressing well, and its completion is expected by June 2023. At the same time, significant progress on the stage 3 protocol work already has occurred.

The Radio Access Network (RAN) Plenary

There were more than 300 in-person attendees at the TSG RAN March 2023 Plenary meeting. RAN is responsible for defining the requirements, functions, and interfaces of the 3GPP radio network.

The plenary allocated additional time to finish the remaining R18 work on New Radio (NR) Network-controlled Repeaters (NCR). This feature will provide improved extension of network coverage on all spectrum bands—when compared to inefficient traditional repeaters—and will be valuable for public safety.

One industry participant proposed that the requirement for 4 receive antennas (4 Rx) in 5G devices be relaxed to 2 receive antennas (2 Rx) for extended reality (XR) goggles and similar user equipment (UE). One drawback of reducing the number of antennas is the projected reduction of network capacity. The main concern is the lack of available space for the additional antennas.

After a lengthy debate, the membership agreed to a way forward to characterize and recognize the form factor limitations of a subset of XR devices, such as goggles, to support 4 antenna ports by the end of June 2023. The follow-up step, if 2 Rx is permitted, will be to identify these 2 Rx devices in the network and to understand impacts to the network and UEs (e.g., performance, coverage, capacity). This feature will facilitate embedding these devices in some personal protection equipment used by first responders.

After an extensive discussion about reducing the cost and complexity, the group determined that the R18 reduced capability (RedCap) UEs will only support a 10 Mbps data rate, while R17 RedCap UEs are projected to support higher data rates with 20 MHz bandwidth. Depending on the usage of these RedCap UEs, this data rate is expected to support many services for public safety.

The group also decided to specify a mechanism to support NR sidelink carrier aggregation (CA) operation based on LTE sidelink CA operation for only Mode 2 operation. In Mode 2, the transmitting UE self-selects the resources according to rules aimed at minimizing the collision risk. The use of CA operation on the sidelink may help public safety when using off-network high-data-throughput services.

The enhanced Uncrewed Aerial Vehicles (UAV) work item will support the regulatory requirements, which include UAV UE identification, avoidance of collisions with other UAV UEs, and support of Broadcasting UAV ID (BRID). Detection and Avoidance also may be supported via the LTE sidelink interface, depending on country-specific regulations. The UAV feature may assist public-safety personnel during search-and-rescue operations.

As part of R18, the group agreed on a new work item that included enhancements for 5G-RAN based Non-Terrestrial Networks (NTN). These enhancements will support new scenarios covering deployments in frequency bands above 10 GHz. The goal is to offer optimized performance while considering the NTN characteristics such as large propagation delay and satellite movement. The use of satellite connectivity can offer many benefits to public safety operating in unserved or underserved coverage areas.

Lastly, enhancement of RAN slicing for NR was specified in R17, defining the slice-aware cell reselection. 5G RAN slicing is a feature built on the existing 5G RAN that strengthens end-to-end network-slicing support for the most demanding service-level agreements meeting Quality of Service (QoS) requirements.

In R18, the group agreed to further enhancements to network-slicing activities in the radio network. These enhancements will support slice-based service continuity. This feature also will allow multiple networks to be created on top of a common physical infrastructure in which each “slice” or portion of the network can be allocated for service-specific needs. Public safety can take advantage of such slicing to satisfy priority and performance goals.

The Service and System Aspects (SA) Plenary

More than 300 participants attended the in-person TSG SA meeting, which is responsible for the overall architecture and service capabilities of 3GPP based systems. The group spent considerable time discussing R19 planning, including a joint session with TSG RAN and TSG CT groups and designating December 2025 as the target completion for R19. Several industry representatives suggested that adding an additional quarter to the R19 schedule would be a better option. Further discussion about extending the schedule likely will happen during the June workshops.

Typically, the SA1 working group works one release ahead of the other 3GPP working groups. This approach helps to define the requirements and use cases for new features, services, and enhancements.

SA1 continues to work on R19 requirements and is advancing work on 25 study items and work items. We are now starting to see work items being introduced as the study items near completion.

Seven study items currently have been moved into work items to begin the normative work. It is expected that most of the remaining study items will be converted to work items by the June plenary meeting.

Progress continues on the study items of interest to public safety. The work on integrated sensing and the study on phase 3 of satellite access have each progressed to 80% completion. Integrated sensing uses 5G radio waves much like radar to sense the position and shape of objects, which promises to increase situational awareness for the first responder. The evolution of 5G satellite access will expand coverage, especially in rural and remote areas.

The SA2 working group reported great progress for R18 architectural technical specifications for high priority items for public-safety work, including:

• 5G proximity-based services (5G ProSe) enhancements to support UE-to-UE relay for extending the range of off-network communications utilizing the 5G sidelink as the radio delivery mechanism;
• 5G multicast-broadcast services (5MBS) enhancements to support clusters of high numbers of public-safety UEs;
• Vehicle-mounted relays (VMR) to extend coverage;
• Ranging-based services and sidelink positioning to provide relative location and direction of public-safety users;
• Support of satellite backhauling in the 5G system (5GS); and
• 5G core-network (5GC) enhancements for satellite access to provide coverage, in case of service interruptions or when a user is in remote areas.

SA2 reported an average 65% completion of these items and is on target to complete these technical specifications by the next TSG SA Plenary meeting in June 2023. There may be some exceptions for open issues related to RAN or to the SA3 security working group.

The SA6 WG develops the architectures for most mission critical (MC) features. The group reported good progress on MC work for R18. All R18 study items are complete and have been transitioned to work items.

The FirstNet Authority continues to be active in completing the work for numerous features supporting public safety. The work on the MC ad-hoc group communications will support the needs for spontaneous communications among MC users. The work on 5G fused location services (5GFLS) continues to improve the accuracy of reported location information. We are also participating in work to enhance MC services, which is 80% complete. This work will support the exchange of location information between 3GPP and LMR (land mobile radio, i.e., legacy public-safety networks) systems.

The Core Network and Terminals (CT) Plenary

More than 200 participants attended the TSG CT Plenary meeting. The CT TSG covers the protocol details that follow the requirements and architectural work performed in the SA TSG. The CT plenary concentrated on advancing R18.

The R18 work is moving quickly from the stage 2 architectural work to the stage 3 protocol-development aspects. Approximately 30 work items were approved to organize the protocol work on R18 features. The work items of special interest to public safety include the Gateway UE function that can connect non-3GPP devices to mission critical applications, architectural enhancements for vehicle mounted relays, and enhancements to the 4G and 5G Core networks for satellite access.

A Gateway UE might be implemented in a police car to allow access from wireless devices near the car to core network mission-critical services. Both the vehicle-mounted relay and satellite access extend coverage beyond the fixed terrestrial network. A stage 3 work item for continued work on the mission-critical applications is expected to be approved at the June 2023 plenary meeting.

The MC test suite development takes place in RAN, and the execution of those tests takes place in the ETSI Plugtest forum. The FirstNet Authority has assumed the task of tracking issues identified in those testing activities, as well as resolving many of the issues in the 3GPP specifications. The protocol changes approved in this CT plenary meeting include resolving several more of those issues, with more solutions are already being pursued offline for eventual approval in June 2023.

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

Other contributors to this article: FirstNet Authority Senior Standards Engineers Jeff Cichonski, Mike Dolan, Ihab Guirguis, Mark Lipford, and Eshwar Pittampalli.