| This paper first discussed the problems about determination of narrow pulse waveforms, the choice of system solutions and application of occasions and so on when ultra-wideband (UWB) wireless technology is used in coal mine communications, and derived the mathematical relationship between the signal transmission power, data rate and transmission distance. For a typical non-carrier 2PAM UWB system, the paper analyzed and simulated the relations between data rate and distance under different conditions, as on the characteristics analysis of first-order and fifth-order Gaussian pulse waveform, it researched the pulse waveform which suitable for mine ultra-wideband wireless communications. Then, the paper introduced the basic concepts of wireless channel transmission mechanism as well as the characteristics of radio wave propagation in underground tunnels; and analyzed the characteristics of several common indoor channel models referred to the establishment of mine UWB channel model. Based on this, this paper focused on the UWB path loss model and the multi-path fading model in mine environment.According to tunnel waveguide mode theory, the paper studied and analyzed the characteristic of hybrid models of the mine tunnel path loss, combining the measured mine UWB simulation environment, pointing out the problems of a hybrid model. Further study of the theory of multi-mode waveguide transmission, the paper determined the selection principle of wave-mode number, analyzed and simulated the phenomenon and characteristics of multi-wave-mode propagation attenuation of the rectangular tunnel. Being different from the wave model theoretical method, based on the theory of mirror, the paper studied ray reflection model, combining with frequency-dependent characteristics of the ultra-wideband channel model, established a mine UWB path loss prediction model for the mirror reflection law, and did propagation loss prediction at the actual measurement environment of the mine UWB and have obtained good forecasting results.Before the study of multi-path fading model, firstly, based on the established reflection model in the mine, the paper simulated and analyzed the propagation characteristics of UWB signals, and obtained that UWB pulse width change will directly affect the system time resolution. Then it studied the pulse waveform distortion from two aspects of the amplitude spectrum and phase spectrum. In addition, did more detailed study for the impact of mine roughness on the propagation characteristics. This paper used the generated Random rough surface function to imitate the rough wall of the mine, using impedance cascade method, that is, the impact of the tunnel wall rough modeled as the impedance of the cascade with a loss, studied the impact of roughness on the propagation characteristics from various angles.The paper focused on mine UWB multi-path fading model in detail, and studied the composite fading model, semi-deterministic statistical model, frequency-domain AR model and frequency-dependent channel model. Firstly, combined with the actual measurement of UWB underground environment, the paper studied the Nakagami multipath fading channel based on the Turin model and did visual simulation by Matlab/Simulink tools, and made amendments to the model, took the shadow fading and rough loss and so on into account, established underground UWB composite fading channel. Secondly, based on the actual measurement environment and connected with IEEE 802.15.3a indoor model, the paper constructed a LOS double-cluster semi-deterministic statistical model, studied the statistical characteristics of UWB channels. Thirdly, this paper studied the frequency-domain modeling method, and model and simulate the UWB indoor and mine environment respectively. Especially, on condition that there is no any information of the channel, the paper combined ray reflection model with the AR method, proposed and established UWB mine multi-path channel prediction-type AR model, verified by simulation. Fourthly, the paper analyzed the building process of the frequency-dependent mine UWB channel model, proposed to extract channel parameters using matrix pencil method; Combined with actual underground frequency-dependent UWB channel, the paper reproduced the channel using matrix pencil method; it is proved to be available for the reproduced channel that is similar to the original one. Based on this, the paper established mine UWB channel model with frequency-dependent and made its simulation and analysis.
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