PSA Discovery Patterns Weekly News Summary

Thu Mar 3 18:08:31 2016

While FirstNet continues responding to the more than 400 questions and while some vendors continue to plan their response while others send their RFP teams home, there is not much more to say about the current situation except that I hope everyone keeps in mind that this network is for Public Safety. It is not a U.S. Government network, it is not a FirstNet network. It is to be a network that enables local, state, and federal Public Safety agencies to have access to a fully secure data and video network that now must also support dial-up telephony, text, and of course, “Mission-Critical” voice in the form of Push-To-Talk (PTT) over LTE.

For a long time now I have been bothered by the use of the term “Mission Critical” and prior to writing this article I researched it in multiple dictionaries, on the NPSTC site, and in the RFP Section J14 Terms of Reference, which offers the following definitions:

MC-PTT “Mission-Critical Push-to-Talk is the standard form of public safety voice communications today. The speaker pushes a button on the radio and transmits the voice message to other units. When they are finished speaking, they release the Push‐to‐Talk button and return to the listen mode of operation.”

And also:

Mission Critical “Any factor of a system (equipment, process, procedure, software, etc.) whose failure will result in the failure of mission operations.”

My problem is with the use of this term as it applies to FirstNet and, indeed, to Public Safety communications of all types. For there to be Mission-Critical PTT over a network, that network, itself, must be considered to be mission-critical. When NPSTC and APCO began work on their Public Safety Grade document that was first provided to the Public Safety Advisory Committee of FirstNet and then to FirstNet, we realized a number of items had to be addressed to provide a true public-safety grade network across which public-safety grade PTT could be used. Since the network is the pipe and PTT is the application that runs in that pipe, if the pipe is not mission-critical or public-safety grade, the applications running across the pipe certainly won’t be.

Let’s look at the differences between a typical Public Safety LMR system and a FirstNet broadband network:

Land Mobile Radio by nature of its development since the 1930s has come to the point where in many cases (but not all) the networks can be considered public-safety grade. This class of network has a number of characteristics that make it so:

  1. First, it is designed to provide its highest level of service most of the time. By that I mean if the network is a P25 trunked system it is operating in this mode most of the time.
  2. However, if there is a problem anywhere in the system for whatever reason, the P25 trunked system can automatically degrade or as I prefer to call it, gracefully degrade to a series of standalone repeaters that still function and provide voice communications.
  3. Should a tower site fail, in that specific area the units can switch to talk-around or simplex (peer-to-many-peer) communications.
    1. Because most portable radios are 5-watt units and mobiles are 30-100 watts, distances that can be covered unit-to-unit are pretty impressive depending on the radio band in use.
  4. LMR systems can also be accessed via radio even when microwave, wired, or broadband connections to the tower have been disrupted.

Shifting the focus now to LTE or broadband cellular networks, we find the following:

  1. At this time, cellular user devices (smartphones, tablets, vehicular modems, sensors, etc.) are designed to be very low power (250 MW or π of a watt). (Note: FirstNet can also employ higher-powered devices but that has a major impact on battery life.)
  2. If the user device is not in range of a cell site then the device the user is holding is nothing more than a paperweight.
    1. A user device, today, cannot communicate with another user device if it is not on the network.
  3. If a cell site is down, units in that coverage area have no access to the network.
  4. Cell sites have more points of failure than LMR sites.
    1. If the fiber-optic cable or microwave feeding the cell site is damaged or out of service, the cell site is down.
    2. Even if the cell site remains live, if it cannot be controlled by the core network (EPC) it is still out of service.
    3. The cell site itself is far more complex than LMR sites, and much of the equipment at the site is software-driven, therefore the potential for outages is higher.

We have been assured by many that the FirstNet system will, in fact, be public safety-grade but the cost to upgrade an LTE network from best effort (the commercial standard) to public safety-grade is an order of magnitude higher. Therefore if the network needs to be built to meet public safety-grade criteria, I don’t think there is any way a vendor can recoup all of the money it will have to invest in this network. The network can probably be upgraded slowly over time in critical areas to provide some type of public safety-grade reliability and, in reality, for more than 98 percent of the time the network will function well I am sure. However, that is a far cry from either mission-critical or public safety-grade.

When I look back at the original concept of the Public Safety broadband network and what it has morphed into, I have to wonder if the end result will be something that will serve the Public Safety community as well as we all expected it would eight or so years ago. We were trying for a modest data and video network, with true pre-emption for Public Safety. Voice was always to have remained on the LMR networks for years after deployment of the FirstNet network, and dial-up, text, and other forms of wireless communications would be handled by existing network operators on their own networks. Now FirstNet is to be a rival to a full-up commercial network with dial-up telephony, text, data, and video and, of course, “Mission-Critical” Push-to-Talk.

Only time will tell how this all turns out. I have to be positive and hope that the issues I see in all of this will be addressed or at least mitigated and the finished product will provide the Public Safety community with the best possible network with the best possible set of services running through a truly secure pipe. So I will continue to poke and prod and ask questions some don‚t think I should be asking. Over the past few weeks some have told me I have been too pessimistic about what lies ahead. Yet the majority of my mail says that the questions I am asking and the concerns I am raising are helpful and that I need to continue.

My goal has always been to help Public Safety get the network it needs and deserves. I will remain hopeful in spite of the many issues that could affect the outcome of this RFP. I will remain positive and steadfast in my belief that the FirstNet folks know what they are doing and have the best interests of the Public Safety community at heart. Yet I am fearful that those behind the curtain who are still pulling the federal strings just don‚t get it and never will. This is not a Federal Network, this is not about Federal priorities and simply letting things work their way through a convoluted system. No, this is about a real need for truly dedicated Public Safety professionals. I hope FirstNet wins out because if not, Public Safety loses once again.

Andrew M. Seybold

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