THE INFLUENCE OF FOREST VEGETATION ON THE RADIO COMMUNICATION CONDITIONS OF THE WIRELESS MODULES ZigBee

Abstract

This paper, ased on the results of experimental studies of the influence of forest vegetation on the transmission of digital signals in a radio channel for ZigBee technology, testifies that there is a zone (with a radius of about 50 m), within which the influence of forest on the loss of packet information does not occur, is suggested: 1) an empirical calculation model for the linear attenuation coefficient, at this its numerical value for the frequency 2.4 GHz is estimated as to amF = 0.5215 dB/m, which is practically close to the value amF = 0.5 dB/m. as per Recommendations ITUR P.833.6., 2) empirical expression determining the dependence of the working attenuation of a radio signal in forest vegetation as the function of the operating frequency and the distance between the transmitting and receiving stations. In recent years, ZigBee technologies are being widely used in the construction of wireless sensor networks, and these technologies are usually used where it is impossible to operate wired sensors. Since in most cases ZigBee networks operate in real terrain conditions, while manufacturers of these networks indicate the range of the transceivers for free space, experimental studies and the construction of empirical formulas on their basis are necessary to assess the impact of forest vegetation on the transmission rate of digital signals and on the range of stable radio communication. The influence of forest vegetation (light forests) on the transmission speed of digital signals is expressed in the fact that there is a zone in which forest vegetation practically does not cause errors in the transmission of packet information in WiFi networks, while in this zone the condition of stable radio communication is fulfilled (power levels at 15–20 dB exceed the sensitivity of the receiving equipment). Outside this zone, forest vegetation causes not only the appearance of the effect of packet loss, but also a decrease in the speed of their transmission and, ultimately, the loss of stable radio communication. Therefore, when using WiFi networks in forest conditions, the radius of stable radio communication at a frequency of about 2.4 GHz should not exceed rF < 50 m.