Analysis Of Radio Propagation Environments To Support Standards Development For Rf Based Electronic Safety Equipment Classic Reprint

Excerpt from Analysis of Radio-Propagation Environments to Support Standards Development for Rf-Based Electronic Safety Equipment The National Institute of Standards and Technology (nist) has been involved in a multi-year project to support the development of performance metrics and test methods for radio-frequency (rf) - based electronic safety equipment used by the public safety community. The work reported here focuses on side-by - side measurements of radio-propagation environment characteristics and actual wireless-device performance in representative emergency responder environments. Identifying the radio-channel characteristics that significantly impair wireless-device performance in various environments enables the development of standardized Iaboratory-based test methods that simulate the conditions under which electronic safety equipment will be used in the field. The test methods can then be incorporated into consensus standards for this equipment. The analysis presented here has been funded by the u.s. Department of Homeland Security's Standards Branch. The work reported here has focused on RF based personal alert safety systems (pass), used by firefighters to indicate when a firefighter is motionless or in distress. However, the methodology and analysis presented here could easily be extended to apply to other types of wireless devices that operate in a point - to - point mode. In the propagation-channel studies, nist engineers measured path loss (attenuation) and the level of reflectivity (or multipath, here quantified by the root mean-square delay spread) in large public structures and environments where radio communications could be difficult. These environments include multi-story buildings; buildings with subterranean floors and tunnels; buildings with deep interior spaces; those with few windows; and outdoor urban canyons, consisting of city streets surrounded by tall buildings. The nist public-safety Communications Research Lab has funded the measurements of the propagation channel. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The National Institute of Standards and Technology (NIST) has been involved in a multi-year project to support the development of performance metrics and test methods for radio-frequency (RF)-based electronic safety equipment used by the public safety community. The work reported here focuses on side-by-side measurements of radio-propagation environment characteristics and actual wireless-device performance in representative emergency responder environments.

We analyze data from NIST field tests in which radio-propagation channel characteristics were measured at approximately the same physical locations where the performance of various RF-based firefighter distress beacons was tested. These side-by-side tests were made in representative emergency responder environments, including an apartment building, four types of office buildings, a convention center, and an urban canyon. These environments contain propagation features that often impair radio communications, including stairwells, basements, and rooms deep within buildings, among others. The goal of this work is to determine appropriate performance metrics for use in the development of laboratory-based test methods for RF-based electronic safety equipment. For the structures we studied, we found that attenuation, rather than multipath, plays a more significant role in determining whether or not a remote distress alarm is received outside the structure. The analysis has enabled rough classification of structures into categories of attenuation values that can be used in laboratory-based test methods to verify the performance of the RF-based alarm system that we tested. The environments, tests, and measured data are discussed in detail.

We analyze data from NIST field tests in which radio-propagation channel path loss values were measured at approximately the same physical locations where the performance of various RF-based firefighter distress beacons were tested. These side-by-side tests were made in two key representative emergency responder environments, a New York subway station and the Empire State Building. These environments contain propagation features that may impair radio communications, including stairwells, tunnels, and rooms deep within buildings, among others. The goal of this work is to determine appropriate performance metrics for use in the development of laboratory-based test methods for RF-based electronic safety equipment. The analysis supports the classification of structures into categories of attenuation values that can be used in laboratory-based test methods to verify the performance of the RF-based alarm systems. The environments, tests, and measured data are discussed in detail. The RF propagation-channel data also provide insight into the expected attenuation in high-rise buildings and below-ground structures.

We analyze data from NIST field tests in which radio-propagation channel path loss values were measured at approximately the same physical locations where the performance of various RF-based firefighter distress beacons were tested. These side-by-side tests were made in two key representative emergency responder environments, a New York subway station and the Empire State Building. These environments contain propagation features that may impair radio communications, including stairwells, tunnels, and rooms deep within buildings, among others. The goal of this work is to determine appropriate performance metrics for use in the development of laboratory-based test methods for RF-based electronic safety equipment. The analysis supports the classification of structures into categories of attenuation values that can be used in laboratory-based test methods to verify the performance of the RF-based alarm systems. The environments, tests, and measured data are discussed in detail. The RF propagation-channel data also provide insight into the expected attenuation in high-rise buildings and below-ground structures.

This thesis analyses how and why culture and geography influence the allocation and licensing of the radio frequency (RF) spectrum in different nations. Based on a broad comparative study of 235 countries, an inter-disciplinary approach is used to explore regulatory frameworks and attitudes toward risk. In addition, detailed case studies of the UK, France, the US and Ecuador provide deeper insights into the main contrasting regulatory styles. Three alternative sociological theories are used to analyse and explain the results for both the in-depth and broad brush studies. The Cultural Theory of Mary Douglas and co-workers is first used to categorise countries in terms of perceptual filters. The empirical findings indicate some countries to be apparently exceptional in their behaviour. The theory of Bounded Rationality is used to investigate and explain these apparent irrationalities. Finally, Rational Field Theory shows how beliefs and values guide administrations in their RF regulation. A number of key factors are found to dominate and patterns emerge. The European RF harmonisation is unique. Following European unification, wireless regulation is divided into two major camps (the EU and the US), which differ in their risk concerns, approach to top-down mandated standards, allocation of RF spectrum to licence-exempt bands and type approval process. The adoption of 3G cellular (UMTS versus CDMA2000) and digital TV standards (DVB-T/ATSC/ISDB-T) around the world reflects geopolitical and colonial influence. The language of a country is a significant indicator of its analogue TV standard (SECAM/PAL/NTSC). Interestingly, the longitude of a country to a fair extent defines RF allocation: Africa and West Asia follow Europe, whereas the Americas approximate the US. RF regulation and risk tolerability differ between tropical and non-tropical climates. The collectivised/centralised versus the individualised/market-based rationalities result in different regulatory frameworks and contrasting societal and risk concerns. The success of the top-down European GSM and the bottom-up Wi-Fi standards reveal how the central-planning and market-based approaches have thrived. Attitudes to RF human hazards and spurious emissions levels reveal that the US, Canada and Japan are more tolerant of these radiation risks than Europe. Australia, Canada, New Zealand, UK and USA encourage technological innovation. A practical benefit of this study is that it will give regulators more freedom to choose a rational RF licensing protocol, by better understanding the possibly self-imposed boundaries of cultural and geographical factors which are currently shaping allocation. Academically, there is utility in undertaking a cultural and geographic analysis of a topic that is mostly the domain of engineering, economic and legal analysts.

Excerpt from Measurements and Models for the Wireless Channel in a Ground-Based Urban Setting in Two Public Safety Frequency Bands This is another in a series of nist technical notes (tn) on propagation of radio signals for emergency-responder communications. Previous technical notes investigated propagation into large building structures (an apartment complex, hotel, office building, sports stadium, shopping mall, etc). Three nist Tech Notes (nist TN 1540, nist TN 1541, and nist TN 1542) described experiments related to radio propagation in a structure before, during, and after implosion. Two subsequent Tech Notes (nist TN 1545 and nist TN 1546) focused exclusively on RF propagation into large buildings, without implosion. Those reports were intended to give emergency responders and system designers a better understanding of what to expect from the radio-propagation environment in disaster situations. The overall goal of this project is to create a large, public-domain data set describing the attenuation and variability of radio signals in various building types and environments in the public safety frequency bands. These studies were funded by the nist Public Safety Research Laboratory within the Office of Law Enforcement Standards. Because the Federal Communications Commission (fcc) has recently opened the spectrum between 764 mhz and_776 mhz for public safety applications, additional measurements were carried out in the 750 mhz frequency band in a dense urban environment (sometimes called an urban We also conducted measurements in this urban environment in the 4900 mhz public safety band (4940 mhz to 4990 mhz represents another licensed public safety band). These measurements were all ground-to-ground with transmitters and receivers at ground level and pedestrian-height antennas to mimic communications between an incident command post and a responder on foot. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The National Institute of Standards and Technology (NIST) with support from the Department of Homeland Security has been working with the National Fire Protection Association (NFPA) to develop standards and test methods for radio-frequency personal alert safety systems (RF PASS). The RF PASS systems are incorporated into a firefighter's gear and are used to alert a base station when the firefighter is in distress, has been motionless for more than 30 seconds, or to alert the firefighter in case an evacuation is necessary. The material here covers the development of several test methods either already adopted by the NFPA or targeted for future revisions of NFPA 1982 Personal Alert Safety Systems. These test methods represent five RF PASS deployment conditions: a highly reflective (high multipath) RF environment; a prescribed amount of attenuation in a point- to-point communication link; a multi-hop connection path; in-band wireless activity; and temporary exposure to high-power, in-band RF interference. The data and developed testing are based on currently used RF PASS frequencies: 450 MHz, 900 MHz, and 2.4 GHz.

An introduction to RF propagation that spans all wireless applications This book provides readers with a solid understanding of the concepts involved in the propagation of electromagnetic waves and of the commonly used modeling techniques. While many books cover RF propagation, most are geared to cellular telephone systems and, therefore, are limited in scope. This title is comprehensive-it treats the growing number of wireless applications that range well beyond the mobile telecommunications industry, including radar and satellite communications. The author's straightforward, clear style makes it easy for readers to gain the necessary background in electromagnetics, communication theory, and probability, so they can advance to propagation models for near-earth, indoor, and earth-space propagation. Critical topics that readers would otherwise have to search a number of resources to find are included: * RF safety chapter provides a concise presentation of FCC recommendations, including application examples, and prepares readers to work with real-world propagating systems * Antenna chapter provides an introduction to a wide variety of antennas and techniques for antenna analysis, including a detailed treatment of antenna polarization and axial ratio; the chapter contains a set of curves that permit readers to estimate polarization loss due to axial ratio mismatch between transmitting and receiving antennas without performing detailed calculations * Atmospheric effects chapter provides curves of typical atmospheric loss, so that expected loss can be determined easily * Rain attenuation chapter features a summary of how to apply the ITU and Crane rain models * Satellite communication chapter provides the details of earth-space propagation analysis including rain attenuation, atmospheric absorption, path length determination and noise temperature determination Examples of widely used models provide all the details and information needed to allow readers to apply the models with confidence. References, provided throughout the book, enable readers to explore particular topics in greater depth. Additionally, an accompanying Wiley ftp site provides supporting MathCad files for select figures in the book. With its emphasis on fundamentals, detailed examples, and comprehensive coverage of models and applications, this is an excellent text for upper-level undergraduate or graduate students, or for the practicing engineer who needs to develop an understanding of propagation phenomena.