The Digital TV Switch And Its Impact On Public Safety

frequency lines A clearer picture wasn’t the only good thing to come out of the switch to digital TV on June 12, 2009. In fact, it was a pivotal day for police and public safety technology in general. It was the date all primary over-the-air TV broadcast transmitters ceased transmitting analog signals and moved to new channel assignments broadcasting in a digital format.

Why did this event have such an impact on law enforcement agencies with technology projects, such as those funded under the COPS Technology Program? The Federal Communications Commission (FCC) reallocated TV channels 63, 64, 68, and 69 for exclusive public safety use. Thus, June 12 marked the date on which public safety could now start implementing systems using this new spectrum—a total of 24 MHz of bandwidth, which almost doubles the historical bandwidth assigned to public safety for wide area mobile coverage.

The potential use of this band goes back to 1999, when the FCC convened the National Coordinating Committee (NCC) to advise it on issues relating to the use of the 24 MHz of spectrum in the 764–776/794–806 MHz frequency bands. Public safety practitioners and subject matter experts, including industry, met and planned for the ordered use of this new spectrum. The major result of the NCC was to divide the 24 MHz of spectrum into a narrowband block and a broadband block.

Narrowband

The narrowband portion was reserved for rather conventional land mobile radio systems. The portion of the 700 MHz reserved for narrowband happens, not incidentally, to be located adjacent to the current 800 MHz allocations.

The result is the ability for law enforcement agencies to consider the inclusion of the new 700 MHz channel in existing systems for expansion of capacity. This was welcome news for many large public safety systems in the major urban areas where all of the existing 800 MHz channels were saturated. Newer radios are capable of bridging the entire range in order to take advantage of this new spectrum.

However, there are qualifications: The FCC added requirements that use of the 700 MHz narrowband must be narrowband digital, specifically Project 25. Other significant features of this band included 32 narrowband channels reserved exclusively for interoperability. This was the first time any channels in any band were designated in a consistent manner nationwide to support interagency and interdiscipline emergency communications.

The result of the narrowband 700 MHz channel allocations enables any public safety agency, that wants to develop a new trunked radio system or expand their existing system, but that had been limited by the lack of available 800 MHz spectrum, to consider a transition to the 700 MHz band. Additionally, those agencies can integrate a much more robust interoperability solution without sacrificing the use of their general use operational channels. The only caveat for these agencies is that the requirement for digital operation may require an upgrade to newer technology in order to comply with the regulations.

Broadband

The more exciting impact on agencies, such as COPS Technology Program grant recipients whose projects are focused on Mobile Data and interoperable voice communications, is that of the digital switch and new access to 700 MHz spectrum (the allocation reserved for broadband services).

Many public safety agencies, law enforcement included, already rely on commercial broadband wireless access delivered by commercial providers such as Sprint, Verizon, AT&T, or other commercial service providers. (This refers not to the hotspot Wi-Fi technology, but the wide area coverage provided through the use of Aircards connected to laptops.) Those agencies using these services are already experiencing the expanded capabilities that broadband wireless brings to their operation. Whereas the limitations of the narrowband channels used for older mobile data terminal (MDT) operations limited applications to basic text messages and data, wireless broadband provides the bandwidth for graphics, images, and even video.

However, it’s been a bumpy road for the 700 MHz broadband allocation. The original distribution of the channel allocations would have been dependent upon Regional Plans administered by Regional Planning Committees similar to the National Standards Policy Advisory Committee 800 MHz allocations. This changed when the FCC determined that the public safety 700 MHz broadband allocation would be assigned to one single nationwide licensee called the Public Safety Broadband Licensee (PSBL).

The entity that received this license was the Public Safety Spectrum Trust, which consists of a consortium of 15 various public safety-oriented associations, including the International Association of Chiefs of Police. The intent was to auction off an additional block of spectrum (called the “D Block”) near the public safety block to private/commercial operations. The rules required that the winning bidder could access the public safety spectrum through a sharing agreement with the PSBL. In the end, no bidder bid the minimum amount specified by the FCC, so the FCC has stepped back to reconsider its next move.

The ultimate end game is that the 700 MHz public safety broadband spectrum will be used to implement a form of national, interoperable broadband network. It may be a combination of local agencies creating local networks independently or in cooperation with commercial service entities. Regardless, the national network (or system of networks) will use commercial technology to provide an experience similar to the current commercial wireless broadband services (but even faster).

The difference will be in the basic requirements specified by the PSBL and the FCC. Being interoperable is paramount on the list. If a first responder is able to operate on a system on the West Coast and needs to work an incident on the East Coast, it will happen. Priority access over noncritical shared use is another requirement (yes, other services will have access to the system in order to provide even more economy of scale). The technology of choice will follow the predominate commercial offerings in order to bring both economy of scale and more graceful technology upgrades in the future. No longer will your kids have a better wireless experience than your everyday work system!

Cost is still a barrier, but there are several issues that should help mitigate the raw cost.

First is cost savings by better management of your resources, not to mention the many agencies already paying ± $50/month per unit for commercial service.

Second, the Broadband Initiatives Program and Broadband Technology Opportunities Program driven by the Department of Agriculture’s Rural Utility Service and Department of Commerce’s National Telecommunications and Information Administration has been soliciting grant applications to assist in deployment of broadband services to rural and under-served areas. While public safety is not a primary target of these grants, the grant language requires the applicants consider public safety in their plans. You will see a mix of schools, states, hospitals, co-ops, and even private enterprise looking for this grant money…and public safety has the extra spectrum required to implement the technology (and leverage the cost of these consortium projects).

Law enforcement agencies planning or implementing a technology project may want to consider aligning with these other grant programs and initiatives to move your project forward.

The Future

Be prepared for big things to come. I, for one, would love to see a conventional-looking 700 MHz public safety handheld providing basic critical public safety voice with a second mode 700 MHz broadband wireless smart phone-like capability all imbedded in the same box. Could it get any better than that?

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