Research And Simulation On Characteristics Of Wireless Channel In The Mine Tunnel

In recent years,the national economy has been growing steadily,which makes the demand for energy keep increasing.Coal industry occupies a pivotal position,coal is still the key energy.The progress and development of wireless communication technology in coal mine promotes the modernization of coal mine production.Coal mine can be divided into non-free transmission channels in restricted space,the research of channel transmission characteristics and channel modeling are of great significance for establishing reliable and secure wireless communication system.In this dissertation,the path loss prediction model of underground wireless channel was established by using support vector machine,according to the characteristics of multi-path fading in coal mine,the MIMO channel propagation model was established by using geometrical optics method,which provided theoretical support for the design of wireless communication system in coal mine environment.Analyzed the attenuation characteristics in wireless communication environment in this dissertation,the roadway is regarded as a hollow dielectric waveguide,using the theory of waveguide mode analyzes the transmission characteristics,summarized the effects of complex factors such as working frequency,antenna spacing,medium parameters,tilt and roughness,etc.The transmission loss model of electromagnetic signal is obtained.On the basis of the previous research,aiming at the large-scale path loss in coal mine,the path loss prediction model based LS-SVM for wireless channel is established,the input of the model is the factor affecting the signal attenuation,and the output is the path loss value.In the process of training model,particle swarm optimization(PSO)is used to optimize the important parameters of LS-SVM model,including penalty factor and kernel function parameters,to improve the accuracy of the model.The simulation results show that the effectiveness of the algorithm is improved compared with the back-propagation neural network,the effectiveness of the algorithm is improved,and the LS-SVM model based on particle swarm optimization can predict the channel fading more effectively,and it can be concluded that the establishment of transmission loss model of electromagnetic signal using support vector machine is a feasible methodAiming at the serious multi-path fading environment in mine,a propagation model(GBDB)based on distribution of scatterers is established,and the MIMO channel characteristics are simulated and analyzed,study the relationship between correlation and channel transmission attenuation,and an improved MIMO system model combined with smart antenna is proposed.The simulation results show that the improved system can effectively improve the transmission rate of the channel and is more suitable for the actual environment of coal mine.