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Photo of a 3GPP meeting room with people sitting at tables and working on computers, overlaid with gear icons and wireless network terminology: “RAN, 5G, V2X, Core, MCdata"

Tech Talk: September 14-21, 2020 3GPP Plenary Meetings Recap

October 8, 2020

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 online September 14-21, 2020. The FirstNet Authority represented public safety interests at the Plenary meetings.


The third quarterly 3GPP Plenary meetings of 2020 recently concluded. As a reminder, the 3GPP Plenary meetings ending in early July officially froze Release 16 (R16) that contains 5G phase 2, as well as additional mission critical services (MCS) features and security enhancements, including basic interworking protocols for connecting an LTE-based MC system to a legacy LMR (land mobile radio) system.

At the September meetings, the 3GPP momentum continued as R17 work is fully under way, including more enhanced mission critical capabilities. Of particular interest to Public Safety are studies for: enhanced location services, unmanned aerial vehicles (UAV) such as drones, direct mode enhancements including sidelink relay, and 5G multicast-broadcast. Many of these studies are already moving into the normative work phase. This and future blog posts will keep you updated on those studies with the biggest impact on MCS for public safety.

The schedule for R17 continues to be a major topic in 3GPP. At this set of Plenary meetings, it was discussed that a new three to six month slip of schedule will occur for R17. A revised schedule will be agreed upon during the December Plenary meetings. A major factor in the slippage is the fact that 3GPP continues to operate with e‑meetings instead of meeting in person. This greatly hampers the ability of delegates to confer outside of the formal meetings to find the compromises that standards are frequently built on.

The following Technical Specification Group (TSG) reports provide details on each of the Plenary meetings with a focus on public safety activities. Representatives from nearly all major mobile equipment vendors, chip manufacturers, software vendors, and network operators from about 35 countries participated, as well as the FirstNet Authority and other government agencies representing public safety interests.

The Radio Access Network (RAN) Plenary

There were slightly over 600 participants in the Plenary meeting for the RAN TSG, which is responsible for defining the functions, requirements, and interfaces of the 3GPP radio network.  

Work items that were completed during the 3rd quarter include: New Radio (NR, i.e., 5G) -based access to unlicensed spectrum, and solutions to enable radio access technology dependent and independent positioning techniques that can meet positioning accuracy requirements for E911 and commercial services.

Progress was reported on R17 study items that include support for even higher accuracy positioning (horizontal and vertical) with lower latency. Ongoing work is also addressing user equipment (UE) power savings requirements, NR sidelink relay, and enhancement of the radio interface for V2X (vehicle to anything). Many of these solutions will be applicable to public safety use cases.

A new work item to specify the RAN enhancements required to support Non-Terrestrial Networks (NTN), a.k.a. satellite, has begun. Issues being addressed include long propagation delays, large Doppler effects, and moving cells in NTN with a single 5G UE. Using satellite access in 5G is an important feature in extending wireless coverage for public safety to underserved areas. This potential future use of NTN was recently discussed by Jeff Bratcher, FirstNet Authority’s CTO/COO, as he updated the Board members during the FirstNet Authority’s September quarterly board meeting about the most recent progress in 3GPP global standards work.

Finally, another topic of particular interest to public safety is the completion of the work on conformance test specifications for the R14 Mission Critical Push-to-talk (MCPTT), MCVideo, and MCData protocols. It should be noted that test specifications always follow a given 3GPP release, since work cannot begin until the standards have achieved significant stability.

The Service and Systems Aspects (SA) Plenary

There were over 300 participants in the Plenary meeting for the SA TSG, which is responsible for the overall architecture and service capabilities of 3GPP based systems. The meeting primarily focused on progressing R17 architecture specifications and R18 requirements.

R18 Stage 1 requirements are still in an early phase, with 14 studies approved. Normative work is expected to start in early 2021 after studies are completed. There are a few mission critical items, including a study of off-network communication for railways (railways are planning to use the mission critical services defined by 3GPP), a study on sharing administrative configuration between interconnected MCS systems, and a study on ranging-based services (estimating distance between UEs) that will define requirements for off-network positioning and ranging. Another study is in progress on vehicle mounted relays (VMR). The goal of this work is to study use cases and potential new service requirements for 5G support of base station relays mounted on vehicles. A VMR may provide another tool for public safety to quickly improve coverage in some scenarios.

Progress has been made on additional key features for public safety such as 5G Multicast-Broadcast services (5MBS) and 5G Proximity services (ProSe). Normative work has also started for satellite access in 5G. Work continues on Stage 2 architectural aspects of MC services such as MCPTT, as well as other verticals like railway and V2X (vehicle-to-everything), which builds economies of scale for public safety. Good progress has been made in spite of the current e‑meeting challenges. The work on location enhancements for MCS that we reported on in our July blog has now begun the normative phase, and the new specification defining MCS support in the IOPS (Isolated Operation for Public Safety) mode of operation was completed. IOPS attempts to maintain communication when one or more cells are disconnected from the core network. Progress was also made on two new study items, one of which is investigating remaining issues with interconnection of different MC systems, and another of which is investigating architecture issues and solutions for a MC Gateway UE function that would support multiple non-3GPP devices connected to 3GPP MCS via the Gateway UE. Finally, work on defining MCS over 5G has been restructured with normative work beginning in well-established areas of 5G, while 5G MC enablers such as sidelink and 5MBS are still under development in other working groups.

A new work item covering MC security was approved. The MCS related enhancements will include improved security for MC media content storage, ProSe, 5MBS and UAVs. During the SA plenary meeting, additional companies requested to be identified as supporting the work item on "Mission Critical Security Enhancements" for R17, indicating a growing interest among many companies in the MC work.

The Core Network and Terminals (CT) Plenary

There were nearly 200 participants in the Plenary meeting for the CT TSG, which covers the protocol details and follows the requirements and architectural work performed in the SA TSG.  

During the past three months, approximately 30 corrections and clarifications were made to R16 and earlier MC protocols. Along with these corrections, there were also four R17 improvements that were approved at the September CT Plenary meeting. These improvements enhance the interworking of MCPTT with LMR systems, and they add preconfigured regroup capability to MCData.

Two MC work items were approved at this meeting for continuing work in R17. The first covers enhancements to MCPTT, and the second covers enhancements to interworking with LMR systems. The FirstNet Authority is the rapporteur of both of these items to ensure their successful completion in R17.

During past European Telecommunications Standards Institute (ETSI) Plugtest events to test MC implementations against each other in a lab environment, 24 issues were found that might impact 3GPP MC standards. The FirstNet Authority and AT&T have created fixes in the 3GPP standards for a number of these issues. The remainder were found to only require an explanation of the standards involved. The FirstNet Authority created responses to almost all of these issues and authored a response liaison to ETSI Plugtest to inform them of the changes to the standards that are being undertaken and provide explanations for most of the other issues.

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