Public Safety Advocate: FirstNet Coverage and PTT

I hope everyone who was able to take time off for Thanksgiving enjoyed the holiday and I want to thank all the public safety personnel who worked last Thursday so the rest of us could spend time with our families and friends. During our trip east, I was keeping tabs on coverage provided by AT&T where we were traveling and while in several states, I talked with the public safety community about today’s AT&T coverage and what might still be needed. Even though a state such as Arizona or Maine has already opted in to FirstNet, it does not mean the public safety agencies are required to make use of the FirstNet/AT&T broadband network. However, since AT&T has already invested a lot of money in the public safety community, and has allocated more money and resources to bring FirstNet up and operational as soon as possible, AT&T would like to have as many public safety customers onboard as possible.

In Arizona where the overwhelming perception within the public safety community was that AT&T’s coverage is not as good as at least one other network operator’s coverage, those who have acquired AT&T devices and done some testing have found that AT&T coverage has increased since they last looked at it. Granted, there are still some spots that need to be covered but several public safety agencies have stated that the FirstNet/AT&T coverage in their jurisdiction is sufficient to join FirstNet and then work with AT&T, federal grants, or in some cases even self-funding additional coverage that AT&T will then include in its overall footprint. There are still some major differences in coverage in some areas, but while it is not possible to see the official FirstNet/AT&T coverage maps over the build-out period, reviewing coverage maps on shows that most of the areas of concern will be covered.

One thing I have found confusing not only for FirstNet/AT&T coverage but for the other nationwide networks as well, is that it is difficult to identify where a network operator owns and runs its own network and where it has contracted with rural carriers to provide coverage to their subscribers. This is important to know because some rural carriers have not yet rolled out LTE and are offering only 2G and 3G, and we are not privy to their build-out plans. I believe that because of the increased push for rural coverage for first responders, as well as the need to provide coverage for rural businesses and citizens, we will see a renewed effort by all of the carriers. As I have mentioned before, we are having success with county and tribal governments that know they want and need coverage beyond what FirstNet/AT&T will bring to their rural areas.

I have also talked to several agencies that want to join FirstNet but are located where there is still not sufficient AT&T or Band 14 coverage. In these cases, the longer-term plan includes staying with an existing provider but not signing a long-term contract, and at the same time working with AT&T on the new coverage they want. It is a must that agencies understand they will not have every square inch of their areas covered. If they reflect on the fact that, today, their Land Mobile Radio (LMR) systems don’t provide 100-percent coverage in their area but usually somewhere between 75 percent and 85 percent of the coverage they would like, and the LMR systems have been around a lot longer than network operators have been deploying fourth-generation LTE broadband, they might gain a better understanding of what is possible and what is not. There is no such thing as 100-percent solid coverage even outdoors, let alone inside buildings.

That is why FirstNet/AT&T has teamed up with a satellite backhaul provider, has a large number of wheeled deployables, and is increasing the number of flying deployables. In addition, companies such as Assured Wireless will be providing higher-power amplifiers for mobile devices (usable on Band 14 only), companies such as Cinetcomm will provide automatic switching between terrestrial LMR and LTE networks and a roof-mounted satellite antenna, Google will provide Loons (which AT&T is using in Puerto Rico with cooperation from Google), mobile LTE modems will provide WiFi access around a public safety vehicle, and much more. Like any network ever built, coverage will grow better over time. In this case, FirstNet has established timelines that must be met by AT&T or penalties will be assessed.  When reviewing coverage requirements, the ingredients for success are a willing partner, a population density that supports new deployments or a need to cover an area for public safety, and finally what the local county or city can bring to the party in the way of additional federal funding or their own investment, as in Harris County, Texas.

Push-To-Talk Over FirstNet/AT&T

Before writing my last article about PTT over the FirstNet/LTE network, I had been told AT&T and Motorola had “mutually” agreed that push-to-talk over FirstNet/LTE would be limited to Motorola’s Kodiak system. After the article was published I received an unofficial communication that stated the Motorola/Kodiak system was the only network-based PTT service that would be permitted until the 3GPP PTT interoperability standard is published but that over-the-top PTT applications such as ESChat and Harris’ BeOn would, in fact, be permitted on the network as long as they were interoperable. So, I started digging into what tools are available to tie a number of different PTT systems together both over the FirstNet/AT&T network and with existing LMR systems.

While I have not completed my research, I hope to gain additional information after this is published. Two hardware solutions from Mutualink and JPS Interoperability Solutions solve the problem I am told, but with a few caveats. There may be others I have not discovered as yet, but it appears from those in the PTT-over-LTE business that the standard P25 ISSI (P25 Inter RF Subsystem Interface) is deemed, at this point, the best solution for all of the many different types of PTT interoperability. (note some ISSI interface systems include proprietary features and  cost more than others ) This would include on FirstNet/AT&T PTT from various vendors, as well as all of these PTT-over-LTE to LMR interface requirements. I will readily admit this is not an area of my expertise but I fully understand the need to ensure FirstNet remains, as promised, a network of open standards, and that PTT systems need to be able to communicate with each other over both the FirstNet/LTE network and to and from LMR systems as well. I hope to have more information available soon and I would hope that at some point we will have an official statement from FirstNet/AT&T regarding the deployment of PTT over FirstNet/AT&T.


It is finally time to concentrate on what will be on the network, who will use it, and how they will use it instead of what we have been doing for the past few years, and speculating about what was to be FirstNet. Now we know. We also know we need to continue to be patient. And we need to keep prodding both FirstNet and AT&T over coverage, PTT services, and probably more issues as they are discovered. There is no doubt in my mind that both FirstNet and AT&T are keeping their focus on the network as a public safety network. Hopefully they won’t lose sight of that.

Some do not like FirstNet’s choice of a vendor and some are trying to derail FirstNet because they were not selected. However, regardless of who won the RFP there would be some who disagree with the award or some aspect of the system. Those who will learn how to make use of the network and come to rely on it will do so only over time as the network is put into place and users kick the tires. Even then, there will be times when things won’t go right, but that happens today with devices, networks, fiber in the ground, and microwave circuits. However, if we have both FirstNet and local LTE networks in place we have a level of fallback from one to the other when it is needed most. Give FirstNet/AT&T a chance as you also make sure they understand your needs and expectations.

Andrew M. Seybold
©2017 Andrew Seybold, Inc.


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