Effects of fire and fire extinguishing on wireless communications in the 2.4 GHz ISM band

Abstract

The objective of this research was to quantify the effects of fuel fire and the follow-on fire extinguishing actions on wireless shipboard communications in the 2.4 GHz ISM band. The attenuation of 2.4 - 2.485 GHz signals transmitted through diesel and heptane fire, water mist created by the fire extinguishing system, and subsequently developed steam, using directional and non-directional antennas with horizontal and vertical polarization, was measured onboard ex-USS SHADWELL using a PC-controlled scalar network analyzer. Statistical analysis of the measured data was performed using a code developed in MATLAB. Whereas, the attenuation for directional antennas exhibits relatively small variations with time and frequency, for nondirectional antennas fire and the follow-on fire-extinguishing phases create severe non-stationary frequency selective fading. Therefore standard communication techniques effective against frequency selective fading (non-stationary but slowly varying with time) are recommended for use with communication systems intended for shipboard indoors use. Even in normal conditions, without fire or water mist/steam, we have determined that frequency selective fading would be a problem for non-directional antennas used in shipboard compartments and thus a system with anti-fading capability should be considered for shipboard indoors use.