The National Institute of Standards and Technology has developed a series of Technical Notes (TN) to support improved radio communications for the public safety community in difficult radio environments.  The study was prompted in part by problems noted during 9/11, which demonstrated some significant shortcomings in the knowledge of radio frequency (RF) propagation in emergency response environments.  This resulted in poor interoperability between radio systems, the inability to communicate with responders deep within structures, and ineffective use of radio transmitters buried in collapsed material (emergency beacons).  Additionally there is a problem broadcasting from large buildings generally.  Three of the TNs describe experiments that measured received signal strength in structures before, during, and after implosion.  The following TNs focus on RF propagation into large buildings, with no implosion results.

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In September 2011, PSCR published a report on in-building Bi-Directional Amplifiers (BDAs).  The report "In-Building Radio Enhancement Systems for Public Safety" (IBRES) was written for public safety communication professionals tasked with assisting building owners in fulfilling in-building public safety communications requirements.  The paper provides:

The paper concludes that when designed, installed, and maintained by experienced professionals, BDAs are considered reliable.  Recent FCC (Federal Communications Commission) rulings that separate low and high site systems into distinct frequency bands have greatly improved reliability.  The FCC is currently working to eliminate interference from substandard BDAs.

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The public safety community requires dependable wireless communications in buildings that often degrade the radio-frequency channel due to construction materials, architectural features, and large physical dimensions.  Here measurements made by the Public Safety Communications Research Program are focused on public safety radio frequencies in large buildings and structures.

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NPSTC has developed a white paper, Best Practices for In-Building Communications, which can be an important resource for public safety agencies. The white paper, developed by the In-Building Working Group of the NPSTC Technology Committee, covers a number of key topics. These topics include information on various ways to attain in-building coverage, sample local ordinances, national-level code initiatives, the proper design and installation of in-building systems, trade-offs among various technology approaches, interference prevention, regulations, and a summary of best practices. In addition, NPSTC partnered with the In-Building Wireless Alliance (IBWA) which developed and conducted a survey of public safety practitioners on the value proposition of in-building communications. The survey results, reported in the Best Practices paper, address future needs for data and video, as well as current voice requirements.

The Best Practices white paper is available for downloading free of charge from the NPSTC home page at NPSTC.org. The paper, which covers a total of 65 pages, is divided into two files -- the main body and the technical appendices. Those interested in the paper are encouraged to download both files. The paper was developed under the leadership of Stu Overby, Chair of the NPSTC In-Building Working Group and approximately 10 contributors from public safety and industry.

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