The devil is in the details for the US FirstNet first responder LTE network

The US First Responder Network Authority has much to contemplate regarding its fledgling nationwide FirstNet broadband network for first responders, argue Mike Hunter and Scott Neal of Mission Critical Partners

The devil is in the details for the US FirstNet first responder LTE network

The Nationwide Public Safety Broadband network (NPSBN), being built under the auspices of the First Responder Network Authority (FirstNet), promises to transform emergency response from coast to coast in the US by dramatically improving the data capabilities of public safety agencies.

Much of this promise stems from the fact that the network will leverage Long-Term Evolution (LTE), which is the same 4G technology being used by the four major wireless carriers in the United States: Verizon, AT&T, Sprint Nextel, and T-Mobile.

The broadband capabilities of LTE will enable first responders to engage in data communications that would be unthinkable over a narrowband network.

But while the NPSBN is full of promise, it will be years, perhaps decades, before that promise is fully realised. In the interim, FirstNet is facing a plethora of challenges that it will need to be overcome. In this article, we examine some of the most important.

Band 14 (700 MHz) devices
One of the big questions regarding the NPSBN concerns the size of the public safety market place that it will serve. Compared with the commercial cellular marketplace, the US public safety market is tiny.

According to the US Department of Labor, Bureau of Labor Statistics, 1.4 million police officers/detectives, firefighters, and emergency medical technicians/paramedics were on the job in 2014. In contrast, it is estimated that about 328 million cellular phones were in use in the US that same year – more than the country’s total population by roughly 10 million.

Consequently, some concern exists – given the relative size of the US public safety market – as to whether commercial wireless device vendors will be willing to make the investment that will be needed to develop ruggedised, public safety-grade devices that are capable of operating on Band 14, the 20 megahertz (MHz)-wide block of 700 MHz spectrum allocated by the US Congress for use by the NPSBN.

The 700 MHz spectrum was chosen for this purpose due to its excellent propagation characteristics; signals in this band penetrate more deeply into buildings – in both urban and rural areas – and cover a larger geographic area with less infrastructure compared with other frequency bands.

The answer to that question is that, most likely, they will. There’s a few reasons for this optimism. First, there are hundreds of thousands, perhaps millions, of supervisory personnel working for public safety and municipal agencies who do not engage in tactical communications; consequently, a ruggedised smartphone will suffice. Corollary to this is the fact that smartphone manufacturers have become quite adept at making their devices impervious to water, shock and dust/sand.

Second, while public safety has been given priority access to Band 14, consumers will also be able to access these airwaves when they are not being used by first responders, for a fee, in order to increase their bandwidth. It is anticipated that Band 14 will be available to consumers as much as 98% of the time.

As a result, expect wireless handset manufacturers to develop dual-chipset devices – one chipset will provide access to Band 14, while the other will provide access to the other cellular bands. In turn, this will result in a wide variety of affordable commercial-off-the-shelf (COTS) ruggedised smartphones that take advantage of economies of scale being made available to the public safety sector.

Additionally, there will be a sizable market for in-vehicle dongles that plug into ruggedised laptop and tablet computers, as well as ruggedised modems that can be mounted in vehicles to support vehicle area networks and/or other devices, all of which will enable Band 14 connectivity.

Form factor
Another issue concerns form factor. Today, fire departments find it challenging to identify PMR devices that are easy to use while wearing heavy firefighter gloves –with knobs and buttons that are easy to turn and push. Given that smartphones are far smaller than the typical PMR device, this certainly presents a design challenge that vendors will find vexing.

Over the short-term, while the NPSBN is used solely as a data network, firefighters will continue to use legacy professional mobile radio (PMR) networks. However, the end game is that the NPSBN will handle both voice and data traffic for all first responders, and legacy PMR systems eventually will become extinct.

Though it is universally acknowledged that the voice and data convergence is years away, it will arrive eventually. When it does, the form factor challenge will need to be solved. In the interim, machine-to-machine devices may be deployed for biometric monitoring or location determination of first responders, particularly firefighters, as an adjunct to voice radio.

Coverage issues
Considerable concern exists regarding whether the NPSBN will be able to provide adequate coverage into rural areas. This is largely because the network will leverage commercial infrastructure, and commercial wireless carriers have not built out adequate infrastructure, such as tower sites, in such areas because there is not enough population density to support the investment.

Put another way, the commercial wireless carriers are in business to make money, and they build their networks in places where they can build a customer base. The problem with this, from a public safety perspective, is that reliable communications are needed wherever emergency response is needed, which is to say, everywhere.

Exacerbating the problem is that the US government only made $7 billion in seed money available to FirstNet, of which about $6.5 billion will be spent on network deployment. It is not nearly enough; most estimates predict that the network implementation costs will fall in a range between $15 billion and $20 billion.

One of FirstNet’s most important tasks, then, is to develop a business plan that will result in a network that not only is implemented, but also will be self-sustaining. Because the ability to do this will depend largely on revenue generated by user fees, the network will be deployed first in places where large numbers of potential users already exist – urban areas.

Genuine worry exists within the public safety sector that the NPSBN will never be deployed in rural areas because of the comparatively small number of potential network subscribers.

There are likely to be coverage challenges in urban areas as well. One such challenge concerns in-building coverage. Even though signals in the 700MHz band penetrate buildings in both rural and urban areas better than other commercial cellular bands, it may not be true that they will penetrate as well as the signals generated by the PMR systems currently used by public safety agencies, which have been optimised for in-building coverage.

If so, this could limit significantly the number of users on the NPSBN, which in turn will have a negative effect on user fees – and ultimately the revenue needed to sustain the network. A workaround can be found in distributed antenna systems (DAS), small cells, and other signal-enhancement technologies, but such solutions are expensive – who will pay for them, and where will the money be found?

Roaming challenge
Roaming represents another significant coverage challenge. When commercial users move into places where 4G coverage isn’t available, they roam onto the carrier’s 3G network.

While this might be annoying to consumers, it would be especially problematic, perhaps life-threatening, if it were to happen to first responders on the NPSBN; one of the key selling points of the network is its expected ability to transmit extremely large data files – such as streaming video and building floorplans and blueprints – that would choke traditional narrowband networks.

While 3G networks are considered to be broadband, a 4G network provides 10 times the data throughput speeds. Without that capability, first responders will not be able to transmit highly bandwidth-intensive data.

Backwards compatibility (and incompatibility) with carriers’ legacy 3G systems is an issue that will be specific to the commercial wireless network associated with the successful contractor in the FirstNet procurement. Each of the major wireless carrier networks is configured differently and, unfortunately, the coverage and capacity are not equal in a market-by-market comparison.

In addition, remember that the plan for Band 14 is to allow consumers to use the spectrum when public safety is not. As the wireless carriers bring more consumers into the band by selling them plans that enable them to leverage the 700 MHz airwaves as a way of enhancing their available bandwidth, the noise floor will increase – and as noise increases, network performance decreases.

This will be a significant problem for any 700 MHz user, but especially first responders whose lives depend on clear and reliable network transmissions. And the more successful the vendors are in this regard, the bigger this problem will become.

Finally, network capacity is another area of concern. In other words, will the NPSBN’s design and subsequent infrastructure be such that it will support a large influx of first responders into an area, as often happens when large multi-jurisdictional emergency incidents occur?

It must if it is to be mission-critical on the level of today’s public safety PMR networks. On a conceptual level, the network could be designed to recognise a large influx of first responders into a cell sector, which would result in pre-emption of consumer users, and even first responders who don’t possess high-enough priority.

But, as always, the devil is in the details. How this issue will be addressed in a workable solution remains to be seen.

Network security, reliability and resilience
FirstNet is counting on the ability to leverage existing commercial infrastructure in order to keep network deployment costs as low as possible, and many tower sites exist that will handle the additional load of NPSBN antennas and supporting technology.

However, many of the potential towers are ageing and not built to current standards, such as those related to wind load and seismic events. Other sites simply aren’t public safety grade; for instance, where most commercial sites use back-up generators that provide about one day’s worth of power, a public safety generator typically provides a week’s worth. Still others won’t be able to handle the additional load.

The bottom line then, quite literally, is that many, if not most, of the commercial sites that the NPSBN potentially would use will need to be hardened, strengthened, and/or brought into alignment with current standards, which will be an expensive proposition.

This leads to an interesting ‘chicken and egg’ question for FirstNet: is it better to place its initial emphasis on network coverage and capacity, or on hardening? On the one hand, if coverage and capacity isn’t sufficient, the network will be of little – or at least, diminished – use to public safety.

On the other hand, if the NPSBN isn’t built to withstand the rigours of a major natural disaster, such as Superstorm Sandy, it will be of no use at all during and after such catastrophic events.

Regarding network security, it appears at this juncture that FirstNet is on the right track, as the data that travels across the network will do so via encrypted tunnels, and in some cases there will be encrypted tunnels within encrypted tunnels.

However, myriad applications will be developed to operate on the NPSBN, and they will need their own security protocols. Right now, it’s just too early to predict how that will transpire.

There is little question that the NPSBN will have a tremendously positive effect on public safety communications once it is deployed. But it is equally clear that FirstNet has a great many questions that it needs to answer before the network comes to fruition.

Firstnet Procurement timeline
• 13 Jan 2016: Requests for proposals (RFP) invited for deployment of nationwide public safety broadband network (core network, transport backhaul, radio access network)
• 10 March 2016: FirstNet pre-proposal conference and public webinar
• 31 May 2016: RFP responses from bidders returned to First Responder Network Authority
• 01 Nov 2016: Award expected by this date.

About the authors
Mike Hunter is director of wireless services and Scott Neal is a senior technology specialist with Mission Critical Partners, a public safety communications consulting firm. MCP is a member of iCERT, the US commercial sector trade association focused exclusively on the emergency response technologies sector.


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