Public Safety Advocate: LMR and FirstNet Attributes

I recently received an email from someone in the industry I know and have worked with on several occasions. He asked if I had ever put together a comparison of Land Mobile Radio (LMR) services with FirstNet/LTE services and networks. Looking back in my archives, I found I have touched on their similarities and differences over the past four or five years but I have never presented a detailed, side-by-side listing of their attributes. For this week’s Advocate I have organized these into one document but I won’t call it a “comparison” since I believe both LMR and LTE networks are and will be required in the public-safety environment for a long time to come. 

This compilation of attributes is not about choosing LMR over FirstNet or FirstNet over LMR. It represents an effort to highlight their advantages and illustrate how public safety benefits when they are used together. I view LMR as the lifeline for public safety and FirstNet as the communications tool that provides those in the field with information about incidents they are responding to, what to expect, what resources are available, and much more in the way of data, videos, and location-based services. An agency that chooses both LMR and FirstNet is one that recognizes that the sum of the two networks is not two, it is more like ten, and if the LMR and FirstNet networks are interconnected at least for Push-To-Talk (PTT), the combined value is even greater. Finally, while I don’t agree with use of the term “mission-critical,” having both networks available to public safety does add redundancy for voice and the combination provides the best public-safety-grade communications available today.

LMR and FirstNet Attributes

CoverageLocal, Regional, StatewideU.S. Nationwide plus Territories
Type of InformationPush-to-Talk Voice: Analog, P25 Conventional, P25 Trunked (some data)Dial-Up Voice, Push-to-Talk, Text, Photos, Data, Video
DevicesMobile, Handheld LMR DevicesSmartphones, Tablets, Mobile Routers
Spectrum Low-band, VHF, UHF, T-Band, 700-800LTE Band 14, All LTE/5G AT&T Spectrum
System TypesSimplex, Repeater, Simulcast, TrunkingLTE Broadband 
PTT SystemsCommon but by TechnologyAt Present, 7 Vendors (1 MCPTT)
InteroperabilityDepends on Spectrum/TechnologyBasic Network Yes, PTT and Apps Not Yet (see Notes)
Device Tx PowerMobile: 50-100 Watts, Handheld 2-5 Watts, External AntennasBasic: 250 Mw (1/4-Watt) Built-In Antennas, Band 14 Only 1.25 Watts
Rx-Tx MatchingGood, may require Satellite Receivers Network Matched Very Well
In-Building CoverageGood to first wall, many buildings have Distributed Antenna Systems Good to first wall, Inbuilding Build-Out in Progress
Handheld Battery LifeNormally One 8-Hour Shift+, Removable and Replaceable Batteries. Rapid Charging AvailableVery Good, Well More than a Shift, Removable Batteries from only a Few Vendors. Fast Charge Available
Voice Security(see notes)Poor on Analog, Better on P25 Conventional, Better on P25 TrunkedFirstNet Fully Encrypted, Secondary Encryption Available as Needed
Site HardeningMost Sites HardenedSites Hardened as Deployed
Power Back-UpBatteries and Generators Are CommonPrime Sites, Yes, Others as Needed
Backhaul Radio, T-1 Copper, Microwave, FiberFiber/Microwave, Satellite in Rural Areas
Network ResilienceSeveral Layers of Degradation Ending with SimplexVulnerable to Site Failure but Designed for Site Overlap, No Simplex 
Failure RecoveryMost Do Not Have Back-Up Systems to Replace Failed SitesFirstNet Deploys Cells on Wheels, In Air, and Other Devices to Restore Service
Investment RequiredBuy and Own System and Devices, Pay for RepairsFirstNet: System Provided; Device Pricing Varies with Device Type
Network CoreAnalog FM – NoneMultiple-Redundant Cores
 P25 Conventional – None 
 P25 Trunked – One Central Core OR 
 Cores Located at Each Site 
 Range Extension  Vehicular Repeaters (AKA Pac-Rat)    Vehicle router using Wi-Fi to devices, High Power on Band 14 only


A number of items do not lend themselves to charts very well, and I did not delve into detailed technology specifications for the various networks as this column is intended to highlight operational similarities and differences. 

There have been recent reports of public-safety LMR disruptions allegedly by protesters. Chicago reported its LMR system was available on the Internet (receive-only) as are most non-encrypted LMR systems, but CBS Chicago reported that radio channels were also being disrupted by music on the channels. This, of course, is a violation of Federal Communications Commission (FCC) rules but it is very difficult to identify those responsible in time to take action. Some Chicago PD personnel were told to use PTT over cellular, which, I believe, means FirstNet since Chicago PD is a FirstNet subscriber. 

It is interesting that while working on this Advocate I received a comment to last week’s off-network column regarding my remarks about security: “Great column as always! I suggest that you tread lightly when you imply FirstNet has the ability to provide ‘secure’ communications. There is the RAN side. Private, yes. However, the subscriber unit uses channelized FDMA to talk-in and the emission can be ‘noticed’ within a local radius. There are techniques to be truly secure, just not in LTE or P25.” This is good advice and I strongly believe in additional security measures for both voice and data on all public-safety networks. 

My last note is a reiteration of something I have been saying all along. The FirstNet network meets the first and most important purpose of the law Congress passed in 2012. It is a Nationwide Broadband Public-Safety Network (NPSBN). Any public-safety agency or personnel with a FirstNet subscription has access to the network regardless of where they happen to be in the United States. What is left to accomplish has more to do with the operational side of nationwide interoperability than it does with the network which is, for the most part, fully operational and far ahead of schedule. 

I am confident the remaining issues will be addressed going forward. These issues include the following: Today there are seven different PTT vendors’ applications available to FirstNet users. The newest is the FirstNet PTT system that is based on and meets the 3GPP Mission-Critical Push-To-Talk (MCPTT) standard. Though three are fully interoperable with each other, there will still be instances during multi-agency incidents when everyone responding may not be able to use PTT over FirstNet because of a lack of full interoperability. This is also true today for many data and video applications used by individual departments and it will be difficult establish a common set of standards for their interoperability. While this is the ultimate goal, it cannot be to the detriment of an agency’s own preferences. Some very intelligent people are addressing this issue and I suspect we will be seeing a relentless movement toward better interoperability. 

The reported interference on Chicago PD’s LMR network and moving users to cellular PTT should be of interest to other departments, especially those still using analog FM or unencrypted digital communications technologies. This strengthens the case for FirstNet—not to replace LMR systems but to augment them. In times of protests or other major events, there is always a chance someone outside public safety will try to interfere with communications. Being able to move PTT activities from LMR PTT to FirstNet during such times makes sense and it provides broader access to agencies reporting to the incident. 

The chart above is not a complete assessment of the two sets of technologies and, as stated, it is not designed to be an either/or chart. Rather, it is designed to show the strengths of each network and reinforce the wisdom of using both LMR and FirstNet. FirstNet provides a level of interoperability among agencies including most federal agencies that are called on to assist in an incident. Access to both networks and, ideally, being able to cross-connect them for PTT services when and as needed, ups communications redundancy and comes closer to a public-safety-grade communications system. 

FirstNet Authority Board of Directors Meeting

The next FirstNet Authority Board of Directors meeting will be held June 17, 2020, from 11:00 a.m. to 1:00 p.m. EDT. This meeting will be conducted via teleconference and open to the public, and it will include committee reports as well as board items and actions. Following FirstNet Authority meetings is a good way to stay current with The Authority, which is responsible for FirstNet, the FirstNet contract with AT&T, and what the future holds for FirstNet. Details for the call-in can be found by following this link.

Winding Down

It seems we have been hit with so many issues right now that involve the public-safety community I have to wonder if any of you are getting any sleep or down time. We are dealing with a nationwide pandemic and nationwide protests that now seem to be peaceful and hopefully will stay that way. A tropical storm is dumping rain, there is lots of rain in the southern part of the U.S., tornadoes continue to pop up, the wildland fire season has started ahead of last year, and the National Weather Service is telling us this could be a bad hurricane season. 

It is encouraging that LMR and FirstNet systems are up and operating, there are back-up capabilities in place that can be tapped when needed, and there are and will continue to be personnel on the ground to help manage the needs of the public-safety community during all this. We will soon learn about new devices that will include both LMR and FirstNet capabilities and some that will feature new and exciting uses of Bluetooth for better coordination of LMR and FirstNet devices. The IWCE conference that was rescheduled for August in Las Vegas has been changed to a virtual conference but I hope many of the vendors will still take part and show us their new devices. So far, the APCO show is still scheduled to be a traditional conference in Orlando. 

The one thing we know for certain is that nothing is certain. This means we need to continue to be prepared for whatever is thrown our way and get past any obstacles. One of the most important tools we have for making our way back to some semblance of normal is an even more solid set of communications systems. However, we need Congress to move toward funding Next-Generation 9-1-1 (NG911), which I believe is the missing link in providing public safety with information they need when responding. NG911 is imperative to FirstNet and LMR will remain part of the equation for a very long time. The ultimate goal is to better prepare those running into harm’s way with the information and tools they need. 

Until next week…

Andrew M. Seybold
©2020, Andrew Seybold, Inc.


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