Analysis of Radio-Propagation Environments to Support Standards Development for RF-Based Electronic Safety Equipment

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.