Research On Through Rock Wireless Communication Technology

Despite of swift and violent development of modern wireless communication technique,there is still devoid of reliable and effective through-rock wireless communication system between the coal mine downhole and the ground,which is a bottleneck for safe production and miing efficiency of coal mine.The traditional downhole wired communication chain circuit has weak resistance to accident.s,thus damage-prone,which tends to incur communication outage between the downhole and the ground,influencing safe production of mine.Thus,the normal downhole operation is pressing for an efficient,reliable,adaptable and fast through-rock wireless communication system.The paper mainly unfolds the following research:Based on an analysis of electromagnetic properties of coal in the rock formation,the paper studies the transmission characteristics and decay characteristics of electromagnetic wave in the coal in the rock formation,The characteristics of electromagnetic wave propagation in uniform coal layer and multiple layered coal channels are studied and analyzed respectively.To establish a ferrite loop-antenna communication model fit for the coal quality in the rock formation according to the decaying condition when the electromagnetic wave penetrates through the coal in the rock formation,with related radiation parameters of antenna optimized in configuration.After defining the rock formation communication model of magnetic coupling form,the paper applies the MATLAB software for numerical calculation for channel communication model of rock formation,and adopts electromagnetic simulation software CST to verify and analyze the result of numerical calculation of communication model.It can be seen from the simulation results of the model that the simulation results of the channel model are extended to the known field environment within a certain calculation error range,which has certain reference value for the design index of the rock communication antenna.It is observed from the CST simulation characteristic curve in a specific electromagnetic environment that it is similar to the amplitude-frequency characteristics of filter.In order to make a simulated test on the whole through-rock wireless communication receiving system,the simulation designs like antifilter circuit for rock formation channel are performed.The design approximates the rock formation channel and transceiver antenna to a signal transmission network,whose transmission characteristics are tested.Lastly,the simulated circuit of rock formation channel and antifilter circuit are cascaded to finish transmission of sound signal.The testing experiment shows that the sound signal severely distorted in terms of wave form after passing the simulated circuit of rock formation,yet the distorted signal was basically restored after passing the antifilter circuit.the rock layer communication analog transmission network has good audio signal transmission effect.This research work provides certain theoretical support for the design of through-rock wireless communication svstem.and has certain practical significance.