Public Safety Advocate: Good News; From One-To-One to One-To-Many

It’s always nice to be able to start an Advocate with good news, especially for both FirstNet and the public safety community. FirstNet (Built with AT&T) updated its subscriber numbers as follows:

The total number of FirstNet subscribers is now more 4 million after the recent addition of 33,400 new subscribers.

In the Field and at Incidents

As most of you know, pre-FirstNet, the mainstay of public safety voice/audio in the field was Push-To-Talk (PTT) voice on Land Mobile Radio (LMR) systems. At the time FirstNet was created, there was already some experimentation with broadband services and both 3G and 4G broadband technologies.

When FirstNet (Built with AT&T) was awarded the contract to build the network in 2017, it was becoming clear that from then on public safety would no longer be restricted to one-way communications (simplex voice). Once the FirstNet network was operational, first responders would also have two-way communications (duplex voice) that smartphones had been providing for a number of years. FirstNet also provides duplex dial-up phone calls, full-duplex video, and data.

A note here. LMR digital trunked radio services are capable of group communications whereas LMR systems provide almost full-duplex audio. When a dispatcher or field unit requests a channel for communications, the request usually includes the dispatcher and a single unit. However, a dispatcher and a group of users, or one-to-many, is typical of non-trunked LMR systems while trunked systems are still one way at a time or simplex.

Along with FirstNet/broadband networks came full-duplex voice communications and other technologies that are now capable of duplex communications. For example, broadband services were already being used on broadband systems around the world. For those who had been using broadband for their own business or personal use, there was not much of a learning curve for making phone calls, sending text messages, and all the other things one can do with smartphones and tablets on broadband networks. People familiar with broadband who became members of the FirstNet nationwide broadband network did not require much in the way of training except for the nuances of some applications including the addition of push-to-talk over cellular.

However, in many cases, those coming from LMR PTT have to be trained in the use of voice broadband services. It is interesting to see that in many cases younger men and women who become members of the public safety community do not need to be taught about the use of a smartphone or tablet. Rather, the voice-only LMR service for their own agency and perhaps agencies they work with require them to be able to move from one channel to another. Of course, this is unfamiliar to a broadband user since with broadband, the network changes the channel (and in some cases moves the mobile device from one band of radio spectrum to another).

In many instances where broadband was adopted, even before FirstNet, education about communications was taking different directions. First, in many cases, younger newcomers were teaching elders (seasoned professionals) how to make the best use of broadband communications. On the other hand, seasoned professionals were giving newcomers lessons in how to operate in the LMR portion of the public safety spectrum.

A Recap

With LMR, there are a number of different technologies and spectrum segments, and within each segment there are a number of unique radio channels. (As mentioned above, digital trunking systems vary somewhat from this model.) Typically, handheld radios are used when outside the vehicle and a higher-powered land mobile radio is usually mounted in the vehicle for use when inside the vehicle.

The range of a typical LMR system is normally the area that covers the city or county or, in some places, multiple cities and counties, and states where statewide LMR systems are shared by many agencies.

Today, LMR and broadband advantages are different in several ways. First, most LMR systems were built prior to broadband by a good number of years. You might recall that last week I mentioned that LMR (then called two-way radio) had been in use since the early 1930s. As the technology was expanded both by the coverage area needed and the number of radio channels (“groups” as in broadband systems) and how users access the various radio channels. With the exception of digital trunked systems, handheld and mobile transmit power for LMR is much higher than a broadband smartphone or tablet. The biggest difference for LMR non-trunked radio systems is that the user in the field is responsible for changing the portion of the spectrum where the radio is operating. Changing radio channels is usually in response to an order from the dispatch system or the incident commander. Those in the field who have been told to move to a channel need to know how to select the assigned channel using their particular PTT application. In the case of LMR, number one is to listen for the radio channel that has been assigned and perhaps what is more important is to return your radio to the main or home channel after the incident is over so you are once again listening to the dispatch center.

One final point is that not all LMR devices being used cover all LMR channels with the radio being used. For many years, each radio only worked on the portion of spectrum for which it was built, and this is still true today in many departments. However, newer radios enable LMR handhelds to cover a number of different radio segments and include radio scanning capability. In most cases, these radios still have to be tuned to the channel indicated by the dispatcher or incident commander. 

I believe both FirstNet and LMR systems will continue to be used into the future, and many will be interconnected. 

The most significant differences between LMR and broadband are as follows:

Broadband systems are not usually operated by someone in the field though in some cases, they can be controlled by the dispatch center, command vehicles in the field, or the emergency command center. Users in the field do not have to change their radio from one portion of spectrum to another and if you asked them what portion of radio spectrum they are currently using, they would most likely be unable to tell you.

It is the network’s job to keep track of all mobile devices in the field. Each network has a number of cell towers associated with it and high-speed fiber or microwave connect the cell sites with what many call the “brains” of the system. A number of other functions are available only on FirstNet and these are available to local-area personnel at the computer system’s end access 

Another big difference is that, as mentioned, cellular networks are controlled by the network. This means if every device on a given network is to be considered available for use on the network, they must be able to communicate in both directions, to and from the cell tower. This is another difference between LMR and broadband. In an LMR radio system, there are times when the field unit can hear the dispatcher but the dispatcher cannot hear the field unit. To make use of FirstNet or other broadband networks, both ends of the radio system must be in contact if the radio in the field is to be considered on the network and operational. This is one reason the missing link in cellular today is known as simplex communications or the ability for field units to talk to each other without having to talk to their network. Today, LMR offers this feature both within the network’s coverage area and also beyond the network’s coverage area. This is a vital feature for public safety since radios are often out of coverage or they need to gain access to areas that are beyond network coverage. A number of companies are working on providing the same type of simplex one-to-one and one-to-many operation via FirstNet and other broadband networks.

I mentioned above that there was a difference in transmit power between an LMR device and a broadband device when public safety’s FirstNet was designed and ready to be rolled out. The public safety community, along with the FirstNet Authority, the 3GPP standards body, and the Federal Communications Commission (FCC) all agreed the one band specifically licensed for public safety (Band 14), the power of a mobile on that portion of the spectrum could be much higher than a typical broadband cellular device. 

Even with this variance, the difference in power levels between an LMR device and the FirstNet device is huge. However, cellular systems are designed to operate over far greater areas than most LMR systems and broadband systems provide services public safety has never before had including, as mentioned, duplex for data, video, and text and the FirstNet users all have full priority and preemption meaning they are the first on a network and the last off. This is one of the major reasons everyone fought so hard to have the federal government provide a portion of the radio spectrum designated for broadband services and, in the case of FirstNet, a single license covering the entire United States.

What’s Coming Next?

The FirstNet network (Built with AT&T) today provides near nationwide coverage, and even though not required, AT&T is adding its new 5G sites that are compatible with FirstNet.

There are a number of different groups that view the future of FirstNet differently. For example, I mentioned simplex or off-network above. A number of us, including myself, are very skeptical that simplex communications over broadband will be as good as today’s simplex over LMR.

Then there are others who believe that in the future (near or far), FirstNet will replace all of the LMR systems in the United States and FirstNet will be the only public safety network in the United States. Here again, I and others continue to believe that both types of networks are needed and, over time, we will be able to communicate across networks. One example today is that there are already LMR public safety systems that have been interconnected to FirstNet so voice traffic or push-to-talk, can be shared across both networks.

Still others believe the ultimate device for public safety will be one that carries both LMR and FirstNet in the same device and is capable of working on both types of networks. A while ago, I wrote a piece about this that appeared in Mission Critical Magazine in which I suggested that we blend the best of FirstNet and the networks’ ability to control communications in the field with aspects of land mobile radio systems that are now available.


Finally, there are a few things all of us who are working to improve public safety communications need to understand. First, the public safety community is very lucky to have a large number of people working on products and services. The list is long but it starts with the FirstNet Authority then FirstNet (Built with AT&T), the Public Safety Advisory Committee (PSAC), which reports to the FirstNet Authority Board of Directors, the Public Safety Communications Research (PSCR) arm of the National Institute of Standards Technology (NIST), public safety organizations such as the International Association of Chiefs of Police (IACP), the major city Chiefs Association, the International Association of Fire Chiefs, the national Association of Sheriffs, APCO, the National Public Safety Telecommunications Council, a large number of vendors, and many more.

The final thought I will leave you with this week is that the nationwide public safety broadband network has been hugely successful. When we were asking Congress for our own portion of radio spectrum for broadband, many of us were worried about several things. Would public safety be able to afford the devices if we cannot generate enough interest for a substantial volume? Cellular operators work with vendors that are interested in selling millions and millions of devices in the public safety community in the United States. Public safety can only be counted as a few million, thus the economics don’t seem to be in favor of what we are trying to do. 

So far, FirstNet has been a great success and much of that success can be attributed to AT&T and others that convinced major broadband device manufacturers to add Band 14 to every phone capable of running on AT&T spectrum. This proved to be a winning combination that created a strong demand for devices that, in turn, enabled vendors to build in quantities that kept prices low. As we have seen since 2017, devices that support FirstNet are refreshed as often as commercial goods and the number of new devices certified by FirstNet (Built with AT&T) increases monthly. It has taken a great deal of work and planning, but as of today, we can declare FirstNet a success and look forward to its continued success well into the future.

Winding Down

The last three issues have more to do with some technology. Today’s and future Advocateslook at the different technologies used by public safety and what engineers who are working on technologies for public safety believe will happen or are trying to make them viable.

Ever since some Members of Congress, the FCC, and the vendor community told the Public Safety Alliance (PSA) and Public Safety Spectrum Trust (PSST) that there was no way in hell we would ever be able to obtain broadband spectrum nor would we get any money to find a nationwide broadband network. It took many years and a lot of work, but finally in early 2012, Congress passed the bill and the President signed a grant what was to become the FirstNet authority with the additional 10 MHz of broadband spectrum we had been asking for, bringing the amount of spectrum for what is now called the “Nationwide Public Safety Broadband Network” (NPSBN)to a total of 20 MHz of 700-MHz spectrum. The public safety spectrum trust already had a license for 10 MHz (5 x 5) and with this new law, another block of 10 MHz was added.

I bring this up because, among other things, I have returned, and I am determined to finish writing my book about what we went through to meet our goal. Many of the people who were deeply involved as we moved closer to convincing those in DC that we really did need the spectrum are still working together today. It’s a shame we did not think far enough ahead to form a legal entity known as the Public Safety Alliance (PSA) because there is more work to be done. MANY of the early members of the group stood up again and we’ve added a few that make the organization stronger. Thanks to the efforts of some members of the group, we now have an organization that is working on other public safety issues. This organization is now known as the “Public Safety Spectrum Alliance” (PSSA) and another organization, which is playing a major role as it ensures public safety continues to work with other beneficial organizations. For example, the Public Safety Broadband Technology Alliance (PSBTA) recently participated in the Vision 2002 conference in Las Vegas.

Prior to and after FirstNet, many of us have come back together and have come to believe that something we said years ago remains just as applicable today. Public safety needs to look out for public safety and continue to work with as many public safety organizations as possible. We have come to understand something we weren’t fully aware of when we began the push for FirstNet. We quickly found out we were not a rich lobbying group throwing money at congressional members so they would vote our way. 

What we did learn is that when the public safety community comes together and embarks on a mission, even when we are told it will never happen, so far, we have been able to make it happen. If you want to make a difference for public safety and public safety communications, reach out to the PSBTA and/or the PSSA. Look at their websites and reach out to someone you may know who is already a member. See how you can be of service to the public safety community.

Until next week…

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


1 Comment on "Public Safety Advocate: Good News; From One-To-One to One-To-Many"

  1. Andy,

    Glad to see that your health is improving.

    There are 5 major criteria for public safety voice communications channels (in order of importance).

    1.) Coverage (Jurisdictional)
    2.) Reliability (Operational Availability)
    3.) Reliability (Talk Capacity)
    4.) Coverage (Adjacent Jurisdiction)
    5.) Coverage (Interoperability)

    Finally, there is the mid criteria of cost/affordability. This includes capital (acquisition/life-time) and operational. It can be refined to metrics of use in feature support (i.e: voice/PTT, data (CAD), video (surveillance, NG911), IOT, +). While making IP based broadband the base transmission protocol of all these needs enables FIRSTNET to be a single, universal transport option, it only works if each category meets the top criteria choices.

    At this time it can be argued that a properly designed and deployed LMR system better meets the needs for the majority regarding the criteria above compared to FIRSTNET for the voice based component of public safety needs.

    As you wrote, FIRSTNET is the child of the search for more public safety spectrum. As in the growth of a human child, the roll-out of FIRSTNET has been affected by the exposure of the growth process to competing interests. The FIRSTNET operational product available to public safety today is essentially the inclusion of particular public safety needs (priority and preemption) into the AT&T commercial network.

    The AT&T network in place has been expanded incrementally with additional 700 MHz spectrum. The amount of D-Block spectrum added, in itself, is not sufficient to accommodate nationwide public safety use with voice as an adjunct to other considered broadband uses (i.e.: video, telemetrics, IOT, etc.) I do not know if this was a primary consideration in the early decisions which resulted in the AT&T award but it is apparent now that without the addition of commercial spectrum, FIRSTNET based on the assigned D-Block only would be limited in providing future comprehensive public safety broadband services.

    At issue is whether commercial base expansion into micro/millimeter spectrum (5G+) will increase (or offset) bandwidth by aggregation to accommodate overall commercial and public safety needs.

    It is obvious at this point that AT&T (or any combination of Carriers) will not meet the ‘universal’ coverage requirement by installation of fixed and permanent site based radio towers. The return on investment is not present. Even with federal, state and tribal grants there will be areas of the US which require temporary mobile/aerial based coverage to achieve coverage for major incidents. The decision process will ultimately depend on a cost/benefit analysis of the particular incident whether or not a deployment (along with the level of support) will occur.

    It is also obvious that millimeter wave use (which provides the most bandwidth improvement) will be economically limited to major metropolitan areas. It will have little additional bandwidth for the vast majority of individual public safety jurisdictions.

    In conclusion, even with the new 3GPP standards for one-to-many (PTT) type communications, it is likely that new broadband demands will stress the AT&T provided availability in the future where frequency blocks <1Ghz will be used (site coverage efficiency). The reduction in PTT voice overhead will be overcome by the demand use (especially in major incidents) of the other categories. Also, the per device fee will rise increasing proportional communications costs to the individual agency.

    I suggest that LMR systems still have a major role to play in the voice component. In the event that major initiatives (grants) are used to provide tower based broadband in rural areas, the most significant impediment to LMR coverage (tower site availability/cost) will be reduced.

    The management trend with many public safety agencies has been to move from owned and maintained individual radio systems to a 3rd-party regional or state service. While in most cases the aggregate cost of operation is higher, the management overhead is eliminated. Few major agencies have adopted FIRSTNET for base voice dispatch and scene communications.

    Perhaps the best alternative for public safety is consolidated LMR systems (in conjunction with regional NG911) which provide voice with better criteria accommodation than FIRSTNET and leaves broadband as the data transport for IP based applications. Not to abandon FIRSTNET as it is an acceptable public safety broadband provider; however, use a tool which is better suited to the particular job at hand.

    In that model, the demand for additional public safety spectrum is offset by the efficiency of universal trunking and P25 modulation. Furthermore, coupling the process with NG911 may (if the proceeds from spectrum auctions appear) be a practical mechanism to fund the process.

    AT&T could 'pull the rabbit out of the hat' by acquiring or joint venturing a satellite provider wrapping the spectrum and coverage into the network. However, the action would require complete handset re-engineering. Couple that with dual commercial and public-safety handset requirements. Also, the looming possibility of monopoly/anti-trust restrictions might deep-six the effort.

    Stay healthy and keep leading the battle . . .

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