Public Safety Advocate: PTT, Data Interoperability Today, —Part 2

In last week’s Advocate, I wrote about how far we have come in meeting our goal of interoperability and outlined some of the major items we still need to address. This week we will take a deeper dive into where we are today and what remains to be done.

First, let’s look at where we are today and what needs to be done this year. Yes, these things can be completed by the end of the year if public safety, FirstNet (Built with AT&T), the FirstNet Authority, and the vendor community can come to a consensus. As I have said before, this is not rocket science. A large number of agencies already use one of the FirstNet-approved Push-To-Talk (PTT) applications over the FirstNet network, over their LMR (Land Mobile Radio) systems, and to and from other agencies. If the vendor community won’t step up and take part in providing nationwide PTT interoperability, today’s FirstNet-approved PTT vendors that interoperate with each other will be able to go it alone and deliver the solution. 

3GPP PTT “Standard”

This year will mark the third year since the introduction of what many were touting as the PTT standard for public safety. “Mission-Critical Push-To-Talk (MCPTT)” broadband devices based on the 3GPP standard are the result. (By the way, where is the Motorola version of MCPT it promised to announce by the end of 2021?) The reality is that the 3GPP MCPTT has not been completed. Many agencies are not waiting around for what is missing: both Android and iOS support, the ability to use more than Radio over IP (RoIP) to provide broadband-to-LMR interoperability, and enough choices of MCPTT-compliant devices that agencies will have the same variety of devices to choose from as they have FirstNet-approved devices.

As I have stated for many months, of the seven PTT vendors approved for PTT over FirstNet, at least four of the seven already support both operating systems, interface with LMR systems using a number of different methods including the 3GPP standard Internetworking Function (IWF), ISSI for P25 Trunked radio systems, CSI, and DSI, for other flavors of LMR systems, including RoIP. Three of the seven vendors are fully compatible with each other and together these three account for at least 50% of the PTT traffic. This includes a large number of federal agencies that can now talk to each other over FirstNet and have bridged their own LMR systems so they are fully interoperable. 

There are still some who believe the 3GPP standard will be the winner in this race to full interoperability, and still others believe it really does not matter if FirstNet PTT can interoperate with LMR PTT since, in their view, “LMR is going away real soon now.” I do not believe that for a minute.

What will it take for a FirstNet organization or some other entity to step in and work with the existing PTT vendors to come up with a common solution for what I believe is the most important missing part of a nationwide broadband network? This missing part is full FirstNet nationwide PTT to enable every agency and first responder to communicate over FirstNet using PTT voice. Then, what will it take to implement a variety of methods to provide easy-to-set up and easy-to-afford FirstNet-to-LMR PTT interoperability. 

We could accomplish this in 2022 if the appropriate people would agree to come together and work out a solution. FirstNet has come a long way in five short years thanks to a lot of hard work and dedication from AT&T, the FirstNet Authority, and others. Since we have such a good, robust nationwide broadband network, I keep wondering why one agency cannot talk to another using PTT on FirstNet.

There are some bright spots when it comes to PTT interoperability. For example, Tango-Tango, one of the three PTT providers that can work with others, has at least one system up and running using Tango Tango PTT (white label ESChat) and Enhanced PTT from Motorola. It is also connected to a number of different LMR systems. The result is that these agencies is have full broadband and LMR interoperability on a daily basis. Why can’t the same be done with all of the agencies and what, exactly is preventing us from expanding this interoperability?

How about all of us who believe interoperable nationwide PTT is a very important feature that has not been available work together to make it happen before December 2022. 

Data Interoperability

Data interoperability is probably the most difficult piece of the puzzle to fit. Many agencies had chosen which applications they would use before there was a FirstNet. As agencies joined FirstNet, they found there had been broadband upgrades to their applications or there were new applications to consider. The issue of course is that data, applications, videos, and photos are created by different applications, which means dissimilar data formats. Unless agencies are using the same application, they will not be able to share data. 

The good news is that some ways have been developed to move all this data over to those who have permission to access it, in whatever formant they need. There are several different solutions. Some have been worked out and are ready for prime time and some are still in development. Either way, this issue is being addressed today. Several times last year I wrote about one way that has been used for videos in several East Coast systems. 

This method of providing data interoperability was recently evaluated by a number of organizations led by SAFECOM NCSWIC. The result of this study is now available in a detailed report that has recently been released: 

_v3_508.pdf) The title of this report is: Approach for Developing an Interoperable Information Sharing FrameworK.

It is a long detailed report on one way to provide data created in any application to be made available to public-safety personnel who do not have a specific application but need access to the data. If all you read is the executive summary you will come away with a good feel for how well this approach has been thought out and how it could enable public-safety users on FirstNet to retrieve any type of data and display it in one or many different formats so it can be reviewed and used. 

The basic premise is to add a layer between the users’ device and the data store. This layer makes use of an Application Programming Interface (API) to extract the data, which is reformatted in the middle layer and, if necessary, sent out to the requesting party in a format suitable for the recipient’s device. 

I have to assume there could be others working on other solutions to the data interoperability issue. However, this is the first solution I have seen in this much detail. This method of data transfer has been used for a number of years in several areas on the East Coast to convert video from one format to another.

I believe this solution has great promise to solve our data exchange problem. It will still take cooperation from software developers to develop Application Programming Interfaces (APIs).  These interfaces extract the data, reformat it in the middle layer and, if necessary, send the data out to the requesting party in a format suitable for the recipient’s device.

It is possible we could see this or some other way to process data so it is accessible to others using different applications this year. Stay tuned!

More to Be Done

Resolution of the two topics above would go a long way toward enabling public-safety FirstNet users to cross-communicate among other FirstNet users. One form uses PTT for voice while another supports the exchange of data that is in a multiplicity of formats. Now that we have the network mostly up and running and more spectrum is becoming available (AT&T’s 5G and hopefully 4.9-GHz that the FCC is re-evaluating), we need to make sure moving around from LTE to 5G and back again is as seamless as we can make. it. 

Later this year, we should see much-needed new and different types of devices for both FirstNet and LMR. Perhaps some will be combined FirstNet/LMR devices. I also believe the number of applications available to the public-safety community will continue to grow. 

The network, users, vendors, and leadership are in place. Now we need to turn our attention to what else we might provide for our first responders. If we can solve both the PTT and data interoperability issues this year, first responders will have two more tools to help them perform their tasks more safely and efficiently.

Network Down Time

The past few years have seen more, larger incidents across the United States. Because so many were more severe, there were more localized or even regional system outages. However, FirstNet, other broadband networks, and land mobile radio networks have fared better. When there is a disruption in service, both the public-safety community and commercial customers on broadband networks are usually affected. If a wireless network goes down for any reason, users who subscribe exclusively to wireless phones and devices cannot even dial 9-1-1 for assistance and they cannot receive updates or even evacuation notifications. Public safety experiences many of the same problems with a few more. Units responding to an incident need to be dispatched and communicate while they are mobile. When they arrive, they need to pass on their initial assessment of the incident. And, of course, the incident commander must be able to communicate with incoming vehicles and personnel and report back to their Emergency Communications Center (ECC).

Having both FirstNet/broadband and LMR offers some redundancy when only one of the systems is down. However, when both are off the air, it creates a critical situation that must be addressed as quickly, efficiently, and safely as possible. 

Many agencies, mainly the larger ones, usually have an in-house staff of engineers and technicians that can be dispatched as needed. FirstNet and other broadband networks also have trained personnel on their staffs but, in many cases, they also have to rely on contractors in addition to those who provide regular services to the cell site(s).

FirstNet and other broadband networks have a number of deployable assets staged and ready to respond as needed. Depending on the location of the incident, status of other incidents, and perhaps the inability to gain access to an incident area, there are and will continue to be delays in putting these deployable assets into service. 

For example, if an incident is weather-related and has been forecast, FirstNet personnel and others will be able to move deployables, personnel, and equipment closer to where they may be needed. Then as soon as it is safe to enter the incident area, network operators can start working to repair the damage. 

Many sites have both generators and back-up batteries, some have only batteries, some don’t rely on the power grid and are instead powered by solar and back-up batteries, and generators. Some smaller sites do not have any emergency power onsite but do have provisions for a mobile generator to be delivered to the site if there is access. 

Even with all this, there are times when sites are off-line and cannot be brought back online due to a number of reasons. For example, a high cell site on a mountaintop might be inaccessible during the winter months or it might be accessible by snow cat or helicopter. Other reasons for site failures are out of the immediate control of the network operator. If the power fails and there is no access for a fuel truck to reach the site and replenish the generator’s fuel, the delay is mostly due to the power company and the weather preventing that site from being turned back on. 

Then there are a large number of fiber-fed broadband sites in the United States where the fiber-optic feed to the cell site is not owned and maintained by the network operator or one of its contractors. Rather, it is brought in by another organization. In this case, connectivity to the site and the ability to bring the site back up rests with the fiber provider. In the Western States we recently saw one company that supplies fiber to a number of sites come out of bankruptcy but it has not stepped up to make repairs in a timely fashion. 

All of this is to say that there are a number of reasons for site failures. If one site in an area fails it is possible that other sites can fill the void until the one site is returned to service. However, in the event of a larger outage such as when the fiber that runs from Southern Arizona north was purposely cut and a long length was removed. It took the fiber company several days to locate and fix the problem. Meanwhile, in the northern part of the state many cell sites belonging to many different network operators were off the air along with a number of 9-1-1 systems. 

The bottom line is that there is no such thing as a network with 5-9’s reliability. Both LMR and broadband network operators are always on the look-out for what could become a single point of failure that would affect network operation. As these are found, they are fixed by adding levels of redundancy. In an Advocate a few weeks ago, I discussed the possibility of redundant backhaul systems for networks. Obviously, this is not often an economically feasible or even possible addition. There are many sites in the United States that have only a single fiber or microwave feed and adding a second would be almost impossible due to the cost. Even so, there are some “key” sites that could be equipped with, for example, a satellite backhaul secondary capability in case of fiber failure. We now have some new methods in addition to gasoline and diesel generators to provide both less expensive and longer lasting back-up power. 

Even with all this there will continue to be network failures. The FCC and all the carriers, especially FirstNet, are working on more redundancy coverage overlap, hardening more sites, and other ways to ensure their networks are as reliable as possible.    

Unfortunately, there is another cause of network outage delays. In many cases, failure of a single or even multiple sites is not raised to the level of a network emergency situation. Recently, there have been times when the local resources were aware of the issues but either did not know how to escalate the urgency of the situation or even how to initiate having it fixed. Years ago, before FirstNet was available, the public-safety community talked about working with broadband network providers to train full-time technicians to assist them when there was a failure in their area. The idea never did gain traction, mainly because network operators did not want non-network or non-contractor personnel working on their cell sites. 

It appears from what I am hearing from the field that the first order of business for addressing out-of-service issues is for each network operator to reach out to an organization that can make sure every possible resource needed for the network to go back on the air can be available on an emergency basis. When lives are in danger, it truly is an emergency situation. 

Let’s see if all of the network operators can become more efficient in handling field issues in a more timely fashion. 

Winding Down

Note: Next week the Advocate will be delayed. The Advocate staff will be traveling most of that week. 

The time for filing reply comments to the Eighth Notice of Proposed Rulemaking for the 4.9-GHz spectrum is now closed. Those who submitted comments and filed reply comments will now wait and see what the FCC Commissioners decide to do. In the Public Safety Spectrum Alliance (PSSA) reply comments, we again made a case for public safety to have access to all 50 MHz of the spectrum, full priority and pre-emption, and provisions for secondary commercial use of the band. The PSSA finally contracted with a company that has worked wth both SAS and ACF for managing spectrum resources. It is clear from this well-written report that neither of these two methods of spectrum management are appropriate or will enable public safety to clear the spectrum of secondary users on a local, regional, statewide, or even nationwide basis. The key to the success of making 4.9 GHz a dual-use spectrum segment is to ensure that first responders do not have to deal with any interference that could impede their use of this spectrum. I am hopeful that the FCC will come to the same conclusions. 

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


1 Comment on "Public Safety Advocate: PTT, Data Interoperability Today, —Part 2"

  1. John Contestabile | January 13, 2022 at 8:52 pm | Reply

    regarding redundancy in the network, as the former SWIC in Md., we connected a statewide microwave system used in the state LMR systems to the the statewide broadband network at several towers where there were points of presence to provide greater reliability and redundancy…wasn’t easy as we were bringing the LMR and IT worlds together, but it has benefits…certainly if a state does not own any broadband assets that is an issue, but with all the infrastructure funding coming, constructing some government owned and operated broadband should be considered….if carefully mapped, the government entities can avoid considerable leased line charges and realize cost savings that will provide a payback over time.

Leave a comment

Your email address will not be published.