Public Safety Advocate: Broadband Interoperability? Z-Axis Location Services, CRDs, Spectrum

There is a lot going on during these early days of 2021. Broadband companies that did not bid on the FirstNet Request for Proposal are seeing how successful FirstNet is and want to change the rules late in the game; initial MegaRange™ drive tests are underway and a webinar is in the making; z-axis location technology is available; and now public-safety agencies are able to own or lease their own mini-emergency Band-14 cell sites.

Network Interoperability—Yet Again?

It seems every time FirstNet (Built with AT&T) releases updates or announces advances, other networks once again bring up broadband interoperability. Recently, FirstNet announced more network growth, new agencies, new subscribers, more Band-14 cell sites, and the addition of z-axis location that enables public-safety personnel to be located to within feet on the exact floor of a building. 

FirstNet announced MegaRange for Band 14, which increases transmit power for mobile devices operating on Band 14 to deliver increased Band-14 range and data capacity. Then it announced that agencies can now purchase, rent, or lease their own mini-deployables to extend network coverage, increase capacity, and serve as emergency FirstNet cells when service is disrupted. Every time we see announcements such as these, Verizon raises its hand and talks about broadband network interoperability as though it is a magic sauce to “fix” public-safety communications, which, of course are not broken.

Verizon’s current set of articles is based on the following statement:

“The time is now, once and for all, for an industry-led approach, leveraging advances in technology to deliver this critical functionality to all public safety agencies and the communities they serve across the nation.” 

When a Nationwide Public-Safety Broadband Network (NPSBN) was first discussed with Congress, the Executive Branch, and the Federal Communications Commission (FCC), Verizon was one of two network operators that supported the concept while both T-Mobile and Sprint fought from the beginning to auction the D-Block spectrum (10 MHz of spectrum adjacent to spectrum already licensed to the Public Safety Spectrum Trust (PSST)). However, once approved, the folks at Verizon who had been supporting the NPSBN disappeared. After The FirstNet Authority began developing its request for proposal, Verizon simply disappeared. 

Verizon’s reappearance and renewed interest in the NPSBN and serving public safety occurred only after the contract was awarded to AT&T and Verizon recognized the success of FirstNet (Built with AT&T). At that point, Verizon began making promises about pre-emption and priority access on its network, though it had told the Public Safety Alliance (PSA) it would never implement them. Verizon launched several attempts to change the basis for how Congress crafted the network to be a single, dedicated public-safety broadband network that would provide nationwide public-safety broadband services for public-safety agencies. At one point, Verizon appears have cajoled folks in the Boulder, Colorado area to file with the FCC demanding that the FirstNet network be opened up to all commercial broadband network operators. 

T-Mobile joined fray and I wrote about how it had fought the concept of an NPSBN long and hard, and how things had seemed to have calmed down until FirstNet stats and its new features and services were made public. Suddenly, this combination of increased subscriber agencies, new features, and new services (some of which are exclusive to FirstNet) seemed to have once again awakened the folks in New Jersey.

Now the dance starts again. Today, three vendors provide cross-network Push-To-Talk (PTT) services via over-the-top PTT applications: ESChat, JPS Interoperability Solutions, and Tango Tango. AT&T (FirstNet) and Verizon provide a Kodiak/Motorola PTT on-network PTT solution that is not compatible across the two networks. FirstNet uses Samsung’s flavor of Mission-Critical Push-To-Talk (MCPTT) and Verizon uses Ericsson’s flavor of MCPTT. Today, these two MCPTT systems do not appear to be compatible cross-network since the standard states MCPTT services are to be maintained inside the broadband network and not over-the-top. MCPTT today supports only some Android devices and no Apple iOS devices. Sometime in the future we should see “InternetWorking Function (IWF), which has been demonstrated by several PTT vendors but has not been implemented by either FirstNet or Verizon. The bottom-line today is that push-to-talk can be used cross-network but not by 3GPP-standard PTT systems, and it is not clear whether different flavors of MCPTT will be fully compatible with each other. 

Further, every LTE network in the world is a little different from every other network because when the 3GPP releases upgrades, network providers do not simply upgrade their networks with each and every element of every release. They pick and choose which pieces and parts they want to install. If you are on the Verizon network today, you can call a phone on any other network in the world, but that is made possible by a third-party organization that provides the interoperability between networks. Access to another network’s “core” (brains) is not available and many engineers I have discussed this with think one network having access to another network’s core opens up issues with security and adds several layers of complexity. 

Connecting different networks directly to each other for the sake of interoperability does not accomplish much, especially when there are other ways to provide interoperability that are much more secure. The way I see it, this comes down to one thing. The public-safety community asked for and was provided with a single, nationwide broadband network for public safety. Those within the public-safety community that do not want finger-pointing when something does not work or is broken have chosen FirstNet because they asked for and received assurances that one entity, The FirstNet Authority, would oversee the build-out, operation, and expansion of the FirstNet system and the winning bidder would build, operate, and upgrade it in accordance with best practices. 

One article about this new push for broadband interoperability stated that public safety is caught in the middle. I disagree. Nowhere in the law are agencies required to move to FirstNet. Today, Verizon, T-Mobile, and smaller broadband operators are providing services to public safety. The decision to move to FirstNet is being made by each agency for a variety of reasons. For example, when concerned about a lack of access to broadband and the Internet due to potential broadband overload, a number of agencies decided to join FirstNet because its 20 MHz of spectrum dedicated to public safety would be available exclusively to public-safety users in the event of congestion. Now that FirstNet offers MegaRange high-power transmit capabilities for vehicular devices, other agencies are considering joining FirstNet based on tests showing increased coverage.  

Public safety is not required to move to FirstNet; agencies move to FirstNet by choice after determining which network will best fulfill their needs. Some agencies have decided to use two or more broadband networks to address coverage issues, and as FirstNet adds Band-14 cell sites over time and now MegaRange, some of these are dropping their second broadband carrier. Agencies using FirstNet enjoy a high level of interoperability. Even so, the issues of 100%-percent push-to-talk interoperability, push-to-talk integration with analog, conventional P25, trunked digital systems, and other digital Land Mobile Radio (LMR) systems have not been fully resolved. Adding other networks into the mix before we have established full interoperability on the FirstNet network does not make a lot of sense. 

Verizon’s or any other non-FirstNet network’s vision of true interoperability between and among networks is not realistic and such interoperability would complicate troubleshooting and maintaining the network’s ability to meet the demands of the public-safety community. Sour grapes combined with a lack of interest in the network early on are not reasons to call for a network that is working well to undergo changes. Everyone should have learned a long time ago that when something works there is no need to fix it. 

Verizon seems to think it is the only one that knows what public safety wants and needs. I say only the public-safety community itself truly understands its requirements and it is working toward providing the services, coverage, devices, applications, and training to meet these requirements. The FirstNet Authority listens to the Public Safety Advisory Committee (PSAC), which plays a critical role in The Authority’s agenda to serve its only customers: the public-safety community. The Authority’s Board of Directors is set up in such a way that law, EMS, and fire are always represented on the board along with the Public Safety Advisory Committee. FirstNet board members are not well-paid, they are serving because they believe in the goals of FirstNet. Their job as a board is not to make sure shareholders realize a great return on their stock investment, rather they are there to make sure the public-safety community has a network that meets its needs and if something fails, only one company is responsible for fixing it. 

While is it being built and operated by AT&T, FirstNet belongs to public safety, not shareholders of AT&T or any other company. It is truly the public-safety network built and operated for public safety and, to my knowledge, it is the only such network in the United States and it needs to stay that way. 

MegaRange™ Drive Testing

For the past month or so I have been one of several people running drive tests with installed MegaRange devices. My Sierra Wireless MG-90 has two radios, one running standard 1/4-watt power on FirstNet and the other running standard 1/4-watt power on Verizon. An AirgainConnect antenna is mounted on the roof of my SUV and it is connected to the MG-90. The Sierra system sees the AirConnect system as a Wide-Area Network (WAN) connection and the MG-90 device and tracking management software sees it essentially as a third radio. 

I have driven 1,705.0 miles in Arizona with the AirgainConnect active and connected to FirstNet for a total of 1,657.8 miles, the standard FirstNet radio was selected for 40.40 miles, and Verizon was the selected radio for 2.29 miles. While we are still gathering test data from my device and others, it is clear that MegaRange increases FirstNet coverage. I cannot state that the unit was always connected to Band 14 as the AirgainConnect and Assured Wireless MegaRange products also contain all non-Band-14 LTE spectrum used by the FirstNet network. 

However, Assured Wireless has provided a new injector that enables me to continue to collect the Sierra Wireless data and to see “inside” the AirgainConnect antenna that is reporting which LTE band it is on during the drive tests. By the time we hold our webinar, we should have some really great data to share on MegaRange devices and the increased range and data speeds they can provide.  

Intrepid and NextNav

One of FirstNet’s major announcements was the addition of “z” height axis. This is a major addition to location determination that, for the first time, enables public safety to track personnel inside buildings in metro areas indicating where they are within the building including the floor they are on and enough data to determine their location on that floor. NextNav has been developing this technology for several years and I wrote a white paper about it in 2015 after witnessing a comprehensive demonstration inside a hotel south of San Francisco. The NextNav technology is based on a series of 900-MHz transmitters installed in metro areas. At that time, the broadband handheld radio had to have an additional built-in chip, but today’s version eliminates the need for the chip and relies on software installed in the devices. 

NextNav has deployed z-axis technology in the Metropolitan Beacon System (MBS) in the top 105 metro areas which, it says, covers 90-percent of all buildings with at least three stories. The system does not rely on WiFi primarily because WiFi is generally not available in buildings during a fire when the power is out. Today, the new location system serves first responders but the ultimate goal is to provide its location capabilities to assist Emergency Communications Center 9-1-1 call takers with better information about the location of callers. In the meantime, NextNav is adding Altimeter technology that will enable application/game developers to bring the 3D world to life by adding vertical dimensions to existing 2D experiences.

Intrepid Networks is providing NextNav data for first responders in its Intrepid Response for FirstNet situational-awareness application that is expected to cost $5 per month but is currently available for a six-month free trial period. As other services begin to use the NextNav/Intrepid system, I suspect the cost for it to be installed on each FirstNet device will decrease. Fire Service is the group most excited about this new addition to FirstNet because firefighters and EMS personnel are the most likely people to be inside buildings during fires and other incidents. Knowing where they are will save lives!

Deployable Cell Sites

Last week I also mentioned Compact Radio Deployables for FirstNet (CRDs) announced by FirstNet (Built with AT&T). FirstNet deploys its Cells On Wheels (COWs), Cells On Light Trucks (COLTs), and other devices including a blimp. These deployables are staged, managed, and deployed by FirstNet as needed. For example, as I write this on Superbowl Sunday, Tampa has staged a number of FirstNet deployables in case they are needed. 

The cost for any of these FirstNet assets to be deployed to FirstNet member agencies is zero, and there has been a great demand for them over the past few years. However, many of us want local agencies to be able buy or lease their own, perhaps smaller, deployable cell sites. CRDs are the answer. CRDs are small enough to be hitched to a vehicle and a number of them can be stored in a trailer for deployment. They will not provide the same level of FirstNet coverage as a typical FirstNet deployable, but claims are they will service an area of one-half to three miles. 

These CRDs can connect to a satellite for backhaul or be connected via several other methods, and they have onboard FirstNet and WiFi for flexibility. They can be mounted on top of a building, on a lower floor with cables up to the antennas, and in many other configurations. The cost to purchase a mini-deployable is around $70,000 with an additional monthly fee for satellite connectivity, or there are lease and rental options.

CRDs are not designed to be purchased and left in the back of a fire station. Like any other tool, they need to be exercised, tested, and put into service during normal training sessions so they can be deployed when needed and put into operation in short order. 

Winding Down

Public-safety communications has a lot of balls in the air. The good news is that the eleven metro areas that were to lose access to the T-Band won’t, and the FCC has freed up these agencies to catch up after almost nine years of not being able to even add a receiver or transmitter to their existing systems. Catching up will take time, and now, of course, there will be even more reports of TV interference to some T-Band systems with the FCC TV rebanding, but I trust these problems will be worked out.

Still open is the case of the 4.9-GHz public-safety spectrum the previous FCC decided public safety really didn’t need, but I suspect the new FCC may have a different view. And we need to be watchful of the now-permitted unlicensed WiFi that will be deployed in 6-GHz critical-communications microwave. Then there is the former FCC’s takeback of spectrum already allocated for traffic safety in the 5.9-GHz band, and the possibility that Ligado’s new Internet of Things (IoT) 5G network in spectrum too close to our Global Positioning System (GPS) receiver band could cause havoc. 

I am hopeful as we move forward that public safety will once again have a seat at the FCC table. Public safety and other critical-communications providers need assurances that they will no longer be pushed aside so spectrum can be re-allocated or shared with those who want spectrum to make money. John Q. Citizen also needs spectrum, but it appears for-profit use has dominated the FCC’s agenda for the past four years. 

Some believe there should be a single pool of broadband spectrum that everyone shares without any distinction between first responders, federal agencies, and teenagers watching videos. This is not a realistic way to view a limited resource and it poses threats to those who need priority access or total access during major disasters or incidents. Many of you are aware of my concerns about pollution of the airwaves and it is happening all too quickly. Rivers that once ran clear are now muddy and polluted, and this is also happening to our radio spectrum. Noise is the enemy of communications. Noise generated by other radio systems, machines, and a variety of other sources reduces the efficiency of our airwaves. 

The simplest illustration of this is to compare how many WiFi access points you once needed to cover your house or office with the increased number you need today for the same coverage and data speeds. The more RF noise and pollution we create, the more difficult it is to communicate over the distances we need at the data rates we want. I hope our new FCC team will involve professional engineers who understand the physics of radio in all portions of the spectrum and who can help decisionmakers to be smart about what to approve and what needs to be sent back for further study.

Until next week…

Andrew M. Seybold
©2021, Andrew Seybold, Inc.


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