煤矿采空区多孔非均匀介质无线信道建模

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中图分类号：TD655 文献标志码：A

Abstract：Existing underground wireless channel modeling mainly focuses on specific scenarios with relatively regular geometricstructures such as roadways，shafts，and room-and-pillarstructures，which is insufficient for goaf scenarios with complexand variable geometric shapesand non-uniformmedia distribution. Forthe porous heterogeneous media environment of coal mine goaf，the bouncing ray method isadopted to establish thewirelesschannel model.First，acoal minegoaf environment model wasestablished，and the bouncing ray method was used to simulate the propagation mechanism of electromagnetic waves in the porous heterogeneous mediaof thegoaf.Directandreflectedpathsbetween transmiter-receiver，transmiter-repeater，and repeater-receiver wereobtained.Then，foreach propagation path，reflection coefcients were introduced to establish the channel impulse response model and the path loss model，and a thermal noise model was constructed by comprehensively considering the goaf environment temperature and the equipment noise coefficient.Finally， through coherent vector superposition of multipath components，the composite received signal was generated. Based on the established porous heterogeneous media wireless channel model of the goaf，the signal-to-noise ratios at frequencies of 0.7， 0.8， 0.9， 2.6，3.5， and 5.9GHz were simulated. The results showed that SNR was significantly negatively corelated with frequency，which was consistent with the theoretical principle of underground coal mine wirelesscommunication， indicating that the established wireless channel model accurately reflected the propagation characteristics of electromagnetic waves at diferent frequencies in the goaf environment. In addition，under the simulated goaf environment， ZigBee and LoRa communication modules were used to conduct received signal strength tests at frequencies of 2.4GHz， 868MHz. and 915MHz with different transmission distances.The test results showed good consistency with the simulation results， verifying the accuracy of the established wirelesschannel model.

Key words： coal mine goaf; porous heterogeneous media; wireless channel modeling; bouncing ray method： electromagnetic wave propagation; multipath effect

0 引言

随着煤炭开采深度和强度的不断增加，矿井地质条件愈发复杂，煤炭开采受到煤自燃与瓦斯复合灾害的严重威胁，同时还易引发粉尘爆炸、矿井通风系统紊乱等次生灾害，煤矿安全生产面临巨大的风险挑战[1-2]。（剩余14035字）