Public Safety Advocate: 3GPP, PSCR, T-Band, Multicast

3GPP, the standards body that created LTE, now seems to be focused on 5G with a few side trips back to LTE. Its Radio Access Network (RAN) Plenary sessions took place at the recent quarterly meeting held in the United States in Newport Beach, Calif. According to Urgent Communications, this event was attended by 325 people representing vendors, operators, and government organizations. The 3GPP has not yet released LTE R16, which is scheduled to be “frozen” in early 2020.

The focus of this session was the development of release 17, tentatively scheduled for finalization in June of 2021. Since extensive details are available from Urgent Communications and the website, here I will briefly touch on some of the issues being addressed. Many of the discussions were focused on 5G compatibility, while other topics included multicast and broadcast. Both of these technologies are necessary for the FirstNet (Built with AT&T) LTE network to be able to dispatch to specific zones or districts in major cities, for example, and not broadcast every incident to the entire area. 

The use of direct-mode in 5G, now called “LTE Sidelink,” is being considered to address the need for direct-mode (off-network) capability in out-of-coverage scenarios. However, I still do not believe LTE or 5G systems will ever replace off-network Land Mobile Radio (LMR). LMR handhelds continue to have major advantages over LTE and 5G off-network devices. LMR handhelds run between 2 and 5 watts depending on the band, and they have external antennas. Even though LMR antennas are not optimal, they perform better than antennas stuffed inside LTE or 5G devices.

Other improvements being reviewed for release 17 include enhanced positioning and Enhanced Multiple Input, Multiple Output (eMIMO), which is jargon for the number of antennas used for each cell and each mobile or portable. More antennas configured to work together result in better coverage and faster data rates. Attention is also being paid to Multi-SIM support (Multi-Subscriber Identity Module). With little Low Earth Orbiting (LEO) satellite systems finding their place, the 3GPP is now looking at Non-Terrestrial Networks (NTNs). (Yet another TLA (Three-Letter Acronym) for you!) 

There are other items under consideration and several stand out as for the benefit of public safety. While the 3GPP is predominantly about commercial wireless and broadband, many years ago the Public Safety Communications Research (PSCR) division blazed a trail for public safety. The FirstNet Authority has submitted its own inputs and they are under consideration. This time around, proposed actions include approval of PSCR recommendations to add new “MCS priority levels to 5G” (Mission Critical Support). This will enable FirstNet to make certain that the same priority and pre-emption available on FirstNet over LTE will be available on 5G. Another FirstNet Authority-led contribution that was approved is adding new User Regrouping to an existing Mission Critical Push-To-Talk (MCPTT) specification. 

It speaks well for PSCR’s efforts over the years that FirstNet and FirstNet Authority are both active in 3GPP, and that the 3GPP community has embraced the public safety community. Together they have worked to identify much of what public safety needs for broadband services within the United States, its territories, and around the world. A lot more was accomplished at this meeting and you can read all about it in Urgent Communications and at


Last week in Chicago, the Public Safety Communications Research (PSCR) division of the National Institute of Standards and Technology (NIST) held its yearly stakeholder conference. Due to prior commitments I was unable to attend but I have followed tweets and reports from others who did. From what I have been reading, this event was once again a hit with attendees. Opening remarks have traditionally been presented by the chairman of The FirstNet Authority and this year’s conference was kicked off by Chairman Edward Horowitz.

Chairman Horowitz praised Sue Swenson, the previous chair who gave the opening speech for the last four years, and he called out Teri Taki, a founding member of FirstNet and the longest serving board member. He then thanked PSCR and its staff for fifteen years of dedication to public safety and what it has done for both land mobile radio and broadband (FirstNet) communications and technologies. One of the Chairman’s messages was, “As more computer power is put into the hands of the end user, there are concerns about information security and patient privacy. How does that impact investment in data management? FirstNet is working hard to ensure first responders and the community can feel confident in the security of their data and personal information.

And at the FirstNet Authority, we need the input of PSCR’s work products to inform future innovations, and we are proud to be a partner with PSCR as we continue to transform public safety communications together.”

He then listed some of the advances that have come about since FirstNet was initiated. “Now, we have a network up and running based on what public safety told us they needed, and it is making a difference in their lives and in the lives of the communities they serve:

  • More than 40 apps have been identified in the FirstNet App Catalog;
  • 75 dedicated deployables — like SatCOLTS and Flying Cell on Wings — are available;
  • More than 100 devices are approved for use on the network through the NIST list maintained by PSCR, giving us the only certified network serving public safety;
  • More than 7,250 public safety agencies have subscribed; and
  • More than 600,000 connections are being used.”

He thanked those in the room who played a part in taking FirstNet to where it is today and the FirstNet Authority roadmap that in 2019 had led more than 600 engagements involving more than 15,000 public safety representatives. This comment confused me as I thought these engagements were to be held in the future to discuss the roadmap and obtain feedback, but perhaps I misunderstood the timing.

The Chairman then presented the FirstNet Authority’s vision for the future:

  • “The FirstNet network Core: We want to ensure the network is technologically current and supports the mission-critical features and capabilities that public safety needs. This means we must continue to evolve and enhance the FirstNet Core for public safety and ensure parity with innovation in the commercial marketplace. We need to ensure the network will be 5G ready and beyond, evolving with technology throughout the life of our 25-year contract and more.
  • Coverage and capacity: We want to make the network available to public safety when and where they need it. This can be macro coverage and capacity, as well as on-demand solutions like the FirstNet-dedicated deployables or in-building coverage. Again this is evolving and advancing the actual buildout of the network to continue to meet public safety’s needs.”

This was followed by what attendees can look forward to learning about at the PSCR event including Situational Awareness, Voice Communications including PTT interfacing with LMR PTT systems, Secure Information Exchange, and a better user experience moving forward. He closed by looking to the future and how FirstNet the Authority will stay laser-focused on the public safety mission, evolving the technologies, public safety’s needs, and partnering with stakeholders.

Chairman Horowitz earned high marks from the press with his comments. It took a while for FirstNet to become truly public safety-oriented but thanks to his predecessors and his own dedication, FirstNet is, as it should be, focused on serving the public safety community. I will report further on the activities at PSCR as they are reported and access is provided on its website.

Winding Down

After the GAO’s report that agencies on the T-Band have nowhere to go and no money from any potential spectrum auction to pay for a move, the FCC concurred that this was the case in most of the metro areas involved. Now is the time to push for the “Don’t Break Up the T-Band Act of 2019 (House Bill 451) to move through the House and be sent to the Senate. Senate Bill 3347, introduced during the 2017-2018 session of the Senate, appears to have been virtually the same as the current House Bill. 

Why has this bill taken so long to pass? Public safety agencies in the metro areas affected AND smaller agencies surrounding them are running out of time and are now facing a crisis. Some say they can simply move to FirstNet, but FirstNet is not yet ready for them. Specifically, network coverage needs to be further expanded and support for simplex communications must be made a part of the network. LTE FirstNet or other networks currently lack support for simplex communications, an essential and often-used radio communications function known as off-network or talkaround, or for IP folks, peer-to-peer communications. This capability is vital to most if not all public safety agencies. Taking the T-Band away in these eleven metro areas will greatly impair their public safety communications systems.

Think about the recent blackout in New York City. Manhattan was dark, elevators were full of people, and riders had to be rescued from the subway system. I’ll bet simplex voice communications between personnel inside buildings was responsible for most communications and most of the rescues. Perhaps those in Congress should give up their cell phones for a week to get an idea of what would happen if public safety had to give up the T-Band. It’s time to act!

I talked about multicast and broadband LTE for FirstNet above. I think these are also vital functions. Today, most major city’s operations are based on zones or districts, and a call-out is directed to specific responders and to others in the district to make them aware of activity within their area of responsibility. Further, multicast can and should be used to send out alerts within districts so they will not disrupt the entire metro area. 

PTT over FirstNet and other LTE networks makes use of groups, which means you can create a group and talk to that group on PTT. How about data and video? To my knowledge, data and video are still limited to one-to-one and are not available for one-to-many. Some people say districts could set up groups and this should work in place of multicast. However, members of groups in a district change from one shift to another. The necessity to change groups with each new shift or incident seems like a time-consuming and inefficient way to replace today’s district dispatch. Many departments have multiple district and citywide channels. Even trunked systems can and do operate with today’s dispatch as well as with groups. 

Those who continue to predict that FirstNet will replace LMR need to make certain that when and if it does, FirstNet is ready for prime time when it comes to all the communications capabilities public safety requires. I remain an advocate of FirstNet and LMR working together and then Next Generation 9-1-1 (NG911) coming online to help personnel in the field to know more about an incident. There are plenty of interesting things ahead for sure. PSCR featured many smart start-ups that are addressing problems that have been identified and hopefully resolved. FirstNet (Built with AT&T), FirstNet the Authority, PSCR, and other organizations are working to equip the public safety community with the communications capabilities it needs when it needs them. Partnerships are a good thing!

NOTE: Next week’s Advocate will be late due to my travel schedule!

Andrew M. Seybold
©2019, Andrew Seybold, Inc.


Be the first to comment on "Public Safety Advocate: 3GPP, PSCR, T-Band, Multicast"

Leave a comment

Your email address will not be published.