Public Safety Advocate: Too Early for LMR vs. FirstNet Rhetoric

It appears as though the more public safety agencies join FirstNet the more those following the progress as “outsiders” (not public safety personnel) are making noises about how FirstNet will “soon” become the only public safety network needed. It is not clear why vendors, pundits, and researchers are pushing this model. It is clear why elected officials in Congress, the states, and local jurisdictions are promoting the one network approach: They want to stop funding existing Land Mobile Radio systems (LMR) that are currently the nearest thing public safety has to mission-critical networks.

Further, some in Congress seem to believe LMR spectrum below 470 MHz can be auctioned for lots of money. I am not sure why some think LMR spectrum is so valuable when it has already been proven that the T-Band 470-512 MHz spectrum used by public safety in eleven major metro areas is not worth much when it comes to auctions. If we continue to allow those who believe giving up the LMR spectrum and putting all of the public safety community onto a single radio system is both the most prudent and economical way forward, we are missing the real issue: What, exactly, are the public safety community’s requirements (not our view but theirs)? We need to let those using the communications networks decide what and where one or both networks will be needed. As I have said before, simply because a technology appears to be ready for prime time, unless it is something the public safety community believes it can trust lives to, it won’t be adopted as the only public safety network regardless of what others say.

I bring this subject up because of the number of related sessions and panels at the recent IWCE conference in Orlando, articles in the trade press, and planned for the upcoming PSCR event in San Diego, the APCO conference in Las Vegas in August, the International Association of Police Chiefs (IACP), and the International Association of Fire Chiefs (IAFC). Technology in the United States, at least, has a tendency to get out ahead of the need or is looked at by those whose smartphone is bonded to their hand, that everything needed in the way of communications can be found either on the smartphone or over the network that powers it. Yet the reality is that while FirstNet is making great strides there are still some limitations with LTE and FirstNet that have not been solved or that have, perhaps, been solved but have not been proven in real-world testing and operation.

It seems to me that these discussions and articles are premature. What is in front of us is bringing up the network, providing the needed coverage, and putting great applications into the ecosystem along with a large choice of devices. Then we need for the public safety community to become proficient at making use of FirstNet for what it does well right now without trying to add things it does not do so well but will perhaps in the future.

FirstNet Today Is about Data and Video Services

FirstNet is being rolled out quickly by AT&T. Band 14 is under construction, devices are becoming more plentiful (NIST’s current list shows seventeen devices approved and more in the pipeline), the network is now end-to-end public safety from the device through the network to the network core, and it is encrypted and as secure as it can be made. Coverage continues to improve. Rural coverage is being implemented and some rural communities are stepping up and funding additional fiber and/or cell sites in order to provide better rural coverage for not only public safety but for all those living and working in rural areas.

FirstNet is being designed to be close to meeting the National Public Safety Telecommunications Council (NPSTC) public safety grade specifications. But is should be mentioned here that LMR public safety grade and FirstNet public safety grade specifications can be met in several ways. LMR has, today, graceful degradation (fallback) while FirstNet/cellular networks do not have the ability to continue to operate in areas where a site has been damaged. We are told there will be work-arounds for this but at the moment there are none.

FirstNet’s PTT is, for now, only available on the network and between the network and existing LMR systems. However, LMR PTT is available in off-network or talk-around mode for unit-to-unit and unit-to-multiple units. Also PTT over LMR works for all LMR radios that use the same analog or digital technology.  This is a must-have for public safety but it appears that the LTE standard known as Pro Se will miss this mark by a long mile. Handheld LMR radios transmit at a power level of about 5 watts (37 dBm) while a typical smartphone transmits at 200-250 milliwatts or 24 dBm. This makes a huge difference in the distance two units can be from each other but the LTE device will most likely need a second receiver or transmitter, adding to the cost where most if not all LMR handhelds already have the off-network talk-around built in. Think about an LMR handheld in a basement talking to an LMR handheld at ground level and outside, which is one way they are used today. Then think about trying to do the same thing with a pair of smartphones with no network access.

PTT over LTE (FirstNet) can be accomplished today, but if the network is down or a device is out of network coverage, there is no way a PTT session can be completed. With LMR, users can switch to direct mode and communicate over a healthy area. During wildland fires, a division or other sub-group may be assigned an area to work the fire. The division chief generally has a radio monitoring the main fire channel but has his or her own division or group using off-network or direct communications. In a major fire it is not unusual for 30-50 simplex channels to be used by different groups. During a police incident, the swat team may be assigned one off-network channel and other units directed to other off-network communications channels. It is this flexibility that makes off-network communications so vital. In reality, off-network or simplex communications is the last in a string of degradable LMR communications as well.

PTT over FirstNet can be of benefit to public safety but not as an everyday, fully capable PTT service. Rather, it can and has been used as the “command-and-control” PTT channel during major multi-agency incidents where those responding are using different LMR radios on different portions of the spectrum and with different analog and digital technologies. This type of command-and-control has been used successfully at several Rose Parades, New Mexico balloon racing events, and many more. It is a logical way to gather groups that need interoperability today on the same PTT service. However, at the moment, even that type of PTT is not available to all departments. Those using one vendor’s PTT can communicate with each other but none of the other vendors seem to be supported at this point. I am told this will change soon and I am looking forward to FirstNet including more PTT options for first responders.

MCPTT?

The 3GPP standards body has dubbed PTT over FirstNet or LTE as Mission Critical PTT over LTE (MCPTT). At this point in time, this term should not be taken to mean PTT over LTE is anywhere near as robust as PTT over LMR is today. There is a lot of work to be done before LTE PTT is ready for its “mission-critical” name to be applied. Even in the UK where the government is promising to move all Tetra traffic to LTE next year or the following year, there is a growing understanding that simplex or talk-around PTT will be handled on existing Tetra  channels and systems.

There are a number of other issues that need to be addressed with LTE before it becomes mission-critical in nature and FirstNet built by AT&T fully understands these issues and is working to resolve them. Among these is the need for multi-cast to be able to send voice and data to more than one device in the field at the same time and using only one voice or data pathway to do so. Today, if I need to send a video to multiple devices I have to send it to them one at a time. This obviously won’t work for large scale incidents but multi-cast will enable the one-to-many services that will be needed and that we understand will also be needed for PTT over FirstNet for operations in areas where only a few cell sectors cover the entire incident.

Perhaps the biggest challenge for FirstNet is that if and when all the technologies are in place so FirstNet can truly provide all the services the public safety community requires. LTE is a flexible platform, dial-up voice, PTT, data, video, pictures, text, and more can be handled across the network and many simultaneously and in real time. When the public safety community says it is ready, when the chiefs will bet the lives of their people to FirstNet, only then will it be time to turn off the LMR networks. That is where those making predictions seem to miss the boat. It matters not if the technology is a standard, it matters not if the technologists state it is ready for service, and it matters not if those who are not using it continue to refer to it as mission-critical. It only matters if those in the field everyday trust it, if it performs as needed when needed, and if the public safety community starts using its LMR radios less and less and its LTE devices more and more.

I also worry about having a single network for all public safety communications. Today our electric grid has been accessed by others in foreign lands, and at some point, could be used to black out a portion or all of the United States. What if FirstNet is the only network available for federal, state, and local public safety services and it is attacked, or hacked, and taken down in an area? How will the public safety community continue to communicate when the network is down? I have been told by people who know that we will be able to communicate (someday) when even a single cell site is up and running. However, at the moment, the limitation to this mode of operation appears to be how you register new users and verify they should have access when a cell site is in standalone mode.

Conclusions

I do wish the pundits, researchers, and vendors promoting all the reporting about LMR and LTE coming together would put a realistic spin on the unknown amount of time before this convergence happens, if it ever does. Why confuse those who are joining FirstNet, learning how to use it, what it can do, and what devices are available with future speak that may be two, ten, or fifteen years into the future? Do any of you really know when the public safety community will tell us it is ready for a single, nationwide network?

It helps that FirstNet built by AT&T is using many different portions of the spectrum and is not confined to band 14 (FirstNet’s spectrum). Most sites are capable of multiple portions of the spectrum so if the tower site is damaged, all the available spectrum for that site may not be usable. I believe FirstNet will come close to being public safety grade over time but I don’t believe we should plan our public safety communications future moves based on driving it from a technology perspective rather than from the users’ perspective.

Let’s spend our time over the next few years making sure FirstNet is a success and that it does what the public safety community has not been able to do before in the field, provides better incident command tools, and applications designed to make those in the field more productive and aid them in their daily routines as well as during incidents. Let’s make sure the devices are the right ones, the applications work and are easy to use, and every first responder, including those who use FirstNet less often, is fully versed in its capabilities and learns how to make the best possible use of them.

Later, as new technologies are proven and accepted by first responders, they can be added to the network but let’s not spend so much time painting a picture that leads elected officials to see signs of green for dismantling LMR systems and budgets. Let’s show these folks what FirstNet is all about and how, for now, LMR and LTE should be working together to provide viable full-function communications tools for public safety.

The next time you are tempted to sit down in front of your keyboard and write about the convergence of LTE and LMR, think long and hard about it, talk to those using it, and then think back to all the things that have been promised to us that we are still waiting for: flying cars, jet packs, and of course wireless services no matter where we are or what our needs are! Think about technologies that were far ahead of their time: Apple Newton, the first laptop, Simon (first smartphone), the General Magic almost-smartphone, and many more. An old boss of mine, before PCs, used to tell me: Paper does not refuse ink! So please be more realistic when your keys leave a trail of words across your screen.

Andrew M. Seybold
©2018, Andrew Seybold, Inc.

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