Public Safety Advocate: PTT vs. MCPTT, 5G Sweet Spot, FirstNet Apps Verified/Certified, 4.9 GHz, Fiber, and More

First, some clarification. “Mission-Critical Push-To-Talk” (MCPTT) is the form of Push-To-Talk (PTT) the 3GPP standards body developed in accordance with its PTT standard. However, networks, including FirstNet (Built with AT&T), are not using the term “mission-critical.” I seem to have confused some readers last week and I have been fielding questions about Motorola’s new offering, which, according to Motorola, will be fully-compliant with the 3GPP standard except it does not support off-network communications (ProSe).

Samsung developed the first PTT to meet the 3GPP standard and it is being offered on FirstNet as “FirstNet PTT.” Motorola’s offering will be the second 3GPP-compliant PTT application available on FirstNet. While it meets the 3GPP PTT standard, it will not use the term “mission-critical” either.

I think it is taking too long to provide a nationwide push-to-talk solution over FirstNet. I do not see any urgency to solve this problem within the public-safety vendor community, but there is a strong sense of urgency from within the public-safety community. 

Some still believe the need for Land Mobile Radio (LMR) systems will diminish and public safety will rely on broadband for all communications. I do not subscribe to this belief. Those who do believe LMR will go away need to recognize public safety’s need for both on-network and off-network PTT that can be accessed by all first responders regardless of where they are. Today, broadband networks cannot provide both. Until they do, there is no way they will ever replace LMR systems. 

The hold-up for push-to-talk interoperability cannot be attributed to the FirstNet (Built with AT&T) network, nor can blame be placed on the inability for some broadband PTT vendors to bridge to any and all existing LMR systems. What it boils down to is that some vendors are still not willing to integrate their solution with other vendors’ solutions or even to come together to discuss the issues that are delaying PTT interoperability. 

As the number of major incidents grows and multiple local, state, and oftentimes federal agencies need to work together, we owe it to first responders to make sure they can communicate among each other. 

We are told there will be a solution soon. However, PTT for everyone is needed now; we can’t wait for “soon” to come around. I have discussed this situation with a number of PTT vendors that provide their own flavors of PTT over FirstNet and with vendors that have connected FirstNet PTT and LMR PTT. While they seem to be willing to work with the others to find a solution, unfortunately, some of the other vendors are not willing to work together. Thus, I don’t agree that this will all be worked out over time. As more, larger incidents require more agencies to respond and work together, an interoperative communications solution becomes more imperative.

5G Sweet Spot

In a recent statement, Jessica Rosenworcel, Acting Chairwoman of the FCC, suggested that the “sweet spot” for 5G network deployment is in the mid-band portion of the radio spectrum. Since there is a lot of confusion today about 5G and data speeds, let’s see if we can explain why 5G data speeds vary.

Currently, 5G Millimeter Wave (MM Wave) spectrum provides the fastest speeds for both outdoor and point-to-multi-point deployment connectivity. Normally, each 5G small cell must be connected back to the network with fiber. Some vendors are using 5G wireless repeaters to increase coverage of their MM Wave 5G cells and they do not need to run additional fiber. However, these systems require many more small cells to cover the same area as a single-cell site using either mid-band or low-band spectrum. 

It is easy to see why there is so much confusion. Today, 5G is being deployed in low-band spectrum (600, 700, 800 MHz), mid-band spectrum (1 to 6 GHz), and Millimeter Wave spectrum (6-50 GHz). Further, we need to learn a number of new 5G terms including New Radio (NR), Stand-Alone (SA) or not part of an existing network, and spectrum slicing.

All this is lumped into “5G” even though capacity, data speeds, latency, and distance covered are very different for each group of frequencies. As with all broadband networks, data speeds are dependent on the amount of spectrum being used; the more spectrum, the higher the data speeds.

5G low-band systems such as the one T-Mobile is building in its 600-MHz spectrum is somewhat faster than an existing LTE network using the same amount of spectrum in the low-band. Low-band 5G cell sites can be farther apart and still provide consistent coverage. 

Mid-band systems are faster and mid-band seems to be where there is enough spectrum to produce high data speeds and low latency. Mid-band requires more sites closer together.

MM Wave systems are fastest. Recorded speeds using MM Wave 5G are much higher than speeds using low-band spectrum. However, MM Wave coverage is not measured in miles, it is measured in football fields. 

Some networks use “carrier aggregation” to increase data speeds. Essentially, this means joining the network you are using, 20 MHz of 700-MHz spectrum for example, with 20 MHz in a different portion of spectrum will result in a 40-MHz network. This 40-MHz network will provide faster speeds than either 20-MHz segment network. This is also true for 5G systems. 

It appears that 5G technology is being used for the new rash of area-wide and inside plants and factories “private” networks. There are more news releases announcing new private networks every week and more are on the way. 

Muni-Networks and Fiber to Premises

Vermont recently announced formation of “CVFiber,” an organization with the goal of providing fiber to every home and business in its member towns to deliver affordable broadband and Internet access. One advantage of fiber over wireless is that fiber provides the same data speeds down-from and up-to the network while wireless networks typically provide higher down-speeds than up-speeds. One disadvantage of fiber to a single location is the expense of running fiber, especially to a single farm, for example, that might require a 10-mile or more run to serve that one property. Another disadvantage is that unless there is wireless broadband coverage in the area, there will be fiber broadband service indoors but not in a wider area outdoors. 

FirstNet (Built with AT&T) Adds Sites and Applications

Every week it seems more Band-14 FirstNet cell sites are being turned on, new agencies are joining FirstNet, and new FirstNet applications are being approved.

Last week was no different. AT&T introduced new applications that include encrypted messaging, video streaming, and video streaming for Unmanned Aerial Vehicles (UAVs, drones) to provide first responders with aerial views of incidents they are headed to or where they are already on scene. 


Also this week, RapidSOS, which provides applications for assisting with emergency responses to more than 5,000 agencies, announced the launch of its website that lists available applications that work with RapidSOS. RapidSOS is building an ecosystem not only to support its own applications but to also include applications from others that add value and capabilities to the RapidSOS system. 

New on

The FirstNet Application Catalog, a dedicated library of evaluated and approved mobile tools for first responders, is now available for viewing at

Every FirstNet-Verified application must satisfy requirements set forth to qualify for the FirstNet-Verified designation, while applications that pass further scrutiny qualify for the higher designation of FirstNet-Certified. Each application version (Android/iOS) is independently reviewed and evaluated, so an application may have two different designations depending on the operating system platform.

This is the first time the catalog has been made available to non-FirstNet users. The list is impressive and it is organized into logical sections so it easy to find applications you might want to take for a test drive to see if they meet your expectations. also introduced a new event designed for the user community. Vision FirstNet Users Summit will be held in Las Vegas January 18-21, 2022, and will feature peer-to-peer networking, customized workshops with industry leaders, and hands-on product testing.

NTIA and the FCC

The National Telecommunications and Information Administration (NTIA) and the Federal Communications Commission (FCC) customarily work together on matters of spectrum since the NTIA is responsible for all federal government spectrum and the FCC is responsible for all spectrum used by non-federal systems including public-safety and commercial broadband services. However, the NTIA, representing fifteen federal agencies, has asked for a stay of the FCC’s 2020 decision to permit Ligado to build out a terrestrial network in L-band spectrum due to concerns about potentially severe interference to the Global Positioning System (GPS) used by many government and civilian companies as well as individuals for location services. 

Even so, the FCC seems to be moving along with its Ligado approval process as many within both the federal government and private sector continue to express their opposition.

If this network is built and it does cause the level of interference the NTIA and other agencies believe it will, the resultant interference problem will be extremely difficult resolve and Ligado will probably be forced to turn off the network. Obviously, it would be advisable to look into this further before any network build-out has begun.

4.9 GHz for Public Safety

I just received the following call for support from the Public Safety Broadband Technology Association (PSBTA). Last year, the FCC voted to reallocate the 4.9-GHz spectrum to the states, taking it away from the public-safety community, which has been using it since 2002. The PSBTA credits the recent “stay” to the efforts of Acting Chairwoman Jessica Rosenworcel to help secure this spectrum. It is imperative that she be named permanent Chair so she can continue supporting public safety in this capacity. Please contact your Senator and email a letter to his/her government email address. An example of what needs to be said follows. 

“As a first responder and resident of (state), I would like to voice my support and recommendation for the nomination of Jessica Rosenworcel as permanent Chairwoman of the Federal Communications Commission (FCC). As you may know, Acting Chairwoman Rosenworcel has distinguished herself as someone who clearly understands public safety and how to balance our needs with the many important policy objectives before the FCC. Public safety has over a decade of experience in working closely with her on these issues, she has earned our trust and respect. I urge you to support and nominate Commissioner Rosenworcel as the permanent FCC Chairwoman as she has proven herself to be an advocate for public safety.”

Broadband for Rural America

As the U.S. Senate remains in DC to work on the infrastructure bill, it appears that funding for rural broadband ($65 Billion) will remain in the bill and the bill will provide for download speeds of 100 Mbps with upload speeds of 20 Mbps, which opens the door for deployment of wireless broadband systems in addition to fiber. The original version of the bill required identical upload and download speeds, precluding use of wireless networks. If the current wording survives the amendment process in the Senate, there will be faster build-outs in rural areas at lower costs than with fiber run to each premises. In addition to solid broadband coverage for businesses and homes via fiber, the inclusion of wireless networks will provide wide-area broadband services those of us who live in more populated areas enjoy. 

Winding Down

August kicks off this season of public-safety events and conferences. APCO in San Antonio is first, followed by the IACP conference and exposition in New Orleans in early September, then IWCE in Las Vegas at the end of September.

I hope the new Delta strain of the Covid-19 virus will not cause any of these events to be cancelled. As I noted before, I will only attend IWCE this year primarily because of my vision impairment and the need for my Editor-in-Chief (she calls herself my “seeing-eye wife”) to travel with me. 

I hope to see many of you at IWCE during the week. I am certainly looking forward to taking part in and listening to many of the sessions and to walking the exhibit floor to find out what is new and what is coming in the not-too-distant future. 

Many vendors, while not attending shows, have been working on new products and services to better serve public-safety and critical-communications users. Perhaps at one or more of these shows we will see what some next-generation devices will look like. 

My bet is we will see more and perhaps different approaches to combination FirstNet/broadband and LMR devices. Vendors are still in search of the “sweet spot” for dual-purpose devices, but at this time, L3Harris and Motorola seem to be leading this segment. I expect to see more dual-mode offerings from the likes of Kenwood, BK, and others and I will be watching to see if dual-mode devices continue to come from LMR vendors or if smartphone, tablet, or other vendors enter this market. 

Many public-safety people I talk with still favor “dual devices” over dual-mode devices. This is understandable since today’s dual-mode devices have not yet been designed to run either Android or iOS applications. At this point, only FirstNet applications are aimed at one or both operating systems. I would not be at all surprised to see a dual-mode device that supports Android, iOS, or both apps—perhaps a beta version if not a device ready for primetime—to measure the interest level among FirstNet users. 

I heard there was a discussion at a recent conference about outfitting multiple fire vehicles (SUVs, engines, trucks) with High Power User Equipment (HPUE) to enable those at an incident to use the Wi-Fi bubble around each vehicle, thereby increasing data speeds for smartphones and tablets, and increasing talk-back data rates and Band-14 coverage. FirstNet (Built with AT&T) has secured the trademark “MegaRange” for this configuration. I am anxious to see if an HPUE/Wi-Fi bubble system can also improve in-building public-safety communications as more agencies test the two different types of high-power Band-14 devices.

Until next week…

Andrew M. Seybold
©2022, Andrew Seybold, Inc. 


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