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January 02, 2008
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Chief Mark A. Marshall The cutting edge of law enforcement technology
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with Chief Mark A. Marshall

Exploring the "wireless spectrum highway"

Okay, here is the first admission I have as a continuing columnist for PoliceOne: I am not a radio head in any sense of the word. When I hear industry experts talk about spectrum, frequency, megahertz, bands, D – E blocks ... it doesn't take long for me to realize I need a translator. Their almost extra-terrestrial language is as familiar to me as ancient Arabic.

But as a police chief I do know that radio spectrum is important. First and foremost, I want my officers to have seamless radio communication without interference. When they push the button and start talking on their radios it is absolutely essential — make that mission critical — that they be able to clearly communicate to dispatch and other responding units the circumstances and situation they are faced with or engaged in. Interference and or non transmission for whatever reason is unacceptable.

Secondly, all of us in law enforcement are trying to capitalize on the accelerated advances of technology. Cell phones, Blackberry, PDA's, MDT’s, video streams and countless other communication devices and applications rely on the radio medium. Most law enforcement agencies recognize that we need to exploit this ever-changing technology. Couple that with the volume of new products, advances, and applications and you have the equivalent of a technology tsunami. It's difficult for even the most “geeked” agency to keep up with.

But we rarely give much consideration as to how the devices connect to each other. That is until they become inoperable, too slow, or require a considerable investment to bring it to contemporary standards. The medium of transport on most of these devices is the "wireless spectrum highway." So, what is that?

Okay, for those of you who are technological wizards you may want to click on to another article. For the rest of us (including myself) here is "Spectrum 101 for Dummies."

"Spectrum 101"

Spectrum is “the range of electromagnetic radiation from the highest frequency to the lowest. It encompasses everything from X-rays and gamma rays to visible light and radio waves”. The physics of spectrum do play a part in the type of services that can be offered. For example the lower the frequency, generally the farther the signal will travel and the better it can penetrate obstacles. A good thing when we are talking about most wireless devices, particularly those that are mobile. Cell phones, radios, broadcasting, and wireless communications operate in a relatively low radio frequency. Lower frequencies also mean cheaper network build-outs and infrastructure. Thus, most of the commercial activity takes place from 30 MHz to 3 GHz.

For reference, broadcast TV and FM radio operate between 54 and 806 MHz. Most cellular services are in the 1710 to 2690 MHz. Most public safety radios operate between the 40 MHz to 800 MHz bands. For example, my agency and the Sheriff’s department operate on a VHF band in the 176 MHz. But most of the surrounding jurisdictions are 800 MHz trunked systems. Even if there was availability to switch to the 800 band (doubtful), the costs are extremely high and require a complete remake of infrastructure.

Who owns the Spectrum?

Technically, the U.S. airwaves (bands) are a publicly owned resource. Like our national parks however, they are regulated by government namely the Federal Communications Commission (FCC). The FCC oversees and grants licenses for companies and or entities to use specific bands/chunks in specific geographic areas. They also regulated in how it may be used.

In years past, the government distributed licenses through a lottery system. But obviously with the rise of cellular/digital services and ever increasing demands the spectrum and more specifically bands became more valuable. Thus many of those recipients started selling their licenses for millions.

Eventually the government caught on and in 1993, Congress authorized the FCC to sell parts of the radio spectrum. As the communications industry grew, so did the demand for spectrum. Remember, that only a small portion of the spectrum is viable for use, particularly from a commercial perspective. The demand for spectrum far exceeds availability.

In an effort to free up space, narrow-banding or halving the space between frequencies has been implemented. Additionally certain portions of the 700 MHz frequency previously occupied by the UHF broadcast TV, was vacated and earmarked for auction in 2008. This created a mad scramble by a number of companies who desired additional spectrum for their commercial interests.

The needs of public safety

Public safety agencies need to have access to a reliable modern technology system that will allow them to communicate with each other seamlessly. The ability to have nationwide roaming capabilities on a wireless broadband network is essential.

In 1995, the FCC created and tasked the Public Safety Wireless Advisory Committee (PSWAC) to provide an assessment of the communications needs of public safety. In 1996, the PSWAC released their report that identified current and future spectrum needs. Among the findings were that 97.5 MHz of new public safety radio spectrum was needed by 2010. In various proceedings 24 MHz was allocated by the FCC at the direction of Congress. Half of this was parceled to urgently needed public safety narrow band voice channels and the remaining half for wideband data channels.

There have been numerous advances in broadband technology, making this application the ideal to consider a national public safety broadband network. Unfortunately however, the current allocation of public safety spectrum is insufficient for a nationwide broadband network.

First, the 12 MHz earmarked for voice channels is desperately needed by public safety. Some of this spectrum is already being used. Other agencies have established plans and considerable investments in infrastructure to take advantage of this allocation. The other 12 MHz designated for data channels is not sufficient in capacity to support both a public safety and commercial interest. Harlin McEwen, retired chief and chair of the Communications and Technology committee for IACP states “ There must be sufficient spectrum for commercial investors to be able to offer reliable commercial services that would not regularly be disrupted by public safety preemption. Without commercial investors, public safety has no funding mechanism to build a nationwide network. Simply put, the only way to build a national network is if more spectrum is made available.

Public Safety Spectrum Trust

The auction of several bands within the 700 MHz spectrum presented the opportunity for public safety to potentially segregate some of these bands for the build-out of a national network. In 2006, resolutions from all of the major public safety associations were passed asking the FCC to designate 30 MHz of the 700 spectrum for the new network. Unfortunately that required Congressional action that was ultimately stymied by vigorous lobbying.

In July of this year the Public Safety Spectrum Trust was created. This Trust was formed by representatives from the International Association of Chiefs of Police (IACP), Association of Public Communications Operations (APCO), and the International Association of Fire Chiefs (IAFC). The Trust petitioned the FCC to become the new National Public Safety Licensee (PSST) for this combined spectrum. It would have the responsibility of negotiating a network sharing agreement with the auction winner of the adjacent spectrum to form the nationwide public-private broadband network. The auction winner would build this network to ensure "interoperability, reliability, redundancy, innovation, and choice for public safety customers using this spectrum." They would include:

• Broadband data services such as text messaging, photos, diagrams and streaming video.
• A hardened public safety network with infrastructure capable of withstanding natural disasters.
• Nationwide roaming and interoperability for local, state, and federal public safety agencies.
• Push to talk, one to one, and one to many radio capabilities that would provide a backup yet not replace current systems.
• Access to satellite services where terrestrial services either do not exist or are temporarily out of service.

Finally, the FCC has approved the concept in principal. The Board of the PSST is represented by 15 members who represent most of the major public safety associations. This Board will guide this process to ensure that this national network deliver a much needed service/infrastructure for all of us in public safety. With the continuing evolution of technology, this important development is vital to our missions. After all, when the spectrum (space) is allocated ... there is no more. We must advocate our needs to ensure that we will be able to fulfill our mandate. Effective and seamless communication is vital to this directive. Anything less is unacceptable.

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About the author

Chief Mark A. Marshall has been Chief of Police in Smithfield, Virginia for over 15 years. He is also the Chairman for the LInX regional information-sharing project, as well as Vice-President for the International Association of Chiefs of Police (IACP). He has oversight of all the technology committees as part of his duties for IACP.

Contact Mark Marshall