Substantiation of the concept of a communication system in the range of medium waves in underground quasi-one-dimensional structures

Background. The modern development of the mining industry is characterized by the search for new mining technologies, increasing the complexity, depth, scale of workings and the danger of work, which leads to the search for approaches in building information and communication systems with increased functionality, namely, with the possibility of combining into a single system of mining automation tools, sensors, tunneling equipment, communication equipment, navigation, controls, equipment operating in an emergency situation. Since most underground facilities can be considered quasi-one-dimensional (mines, subways, sewers), transmission lines laid along tunnels can be effectively used to organize data transmission in them. Aim. Consider the physical side of the operation of the information and communication system in the medium and high frequency ranges. Methods. The dependence of the field strength in a tunnel with single-wire and bifilar lines laid in the tunnel was obtained using electrodynamic modeling by the finite element method. Results. The values of attenuation in workings with different medium parameters and attenuation dependences obtained experimentally in a coal mine are given. On average, the signal attenuation is 15 dB per 1 km. Conclusion. A digital medium-wave system based on bifilar lines has significant advantages when deployed over VHF communication systems. It can be used as a base, and if necessary, supplemented with VHF technologies (Bluetooth, Wi-Fi), for example, for personnel using an explosion-proof smartphone, and in areas where increased throughput is required, in places of active mining operations in mines and concentration of technological equipment and personnel.