巷道无线信道相干带宽及其影响因素的研究

A Study of Coherence Bandwidth of Wireless Channel and its Influencing Factors in Tunnel

研究信道相干带宽可以提高矿井通信的性能,提高传输效率。巷道内环境复杂,电磁波局限于巷道内,造成在巷道内比地面上更大的多径衰落,设计无线通信设备时难度系数较大。研究巷道无线信道相干带宽及影响因素,为优化设计通信设备提供理论支撑。提出在矿井巷道电磁波传播的多波模理论的基础上,利用软件模拟法对煤矿巷道中的无线信道进行建模,分析载波频率、传播距离、巷道形状等对信道相干带宽的影响,得出以下结论:相干带宽随频率的增加而增加,增加到一定之后趋于恒定;随传播距离的增加而降低,距离达到一定时趋于稳定;在矩形巷道内,频率一定时,相干带宽随形状因子的增大先增大后减小,巷道宽高相同时最大;在矩形巷道横截面积一定时,相干带宽随形状因子的增大先增大后减小,巷道宽高相同时最大。

Based on the muhimode theory in mine tunnels, a wireless channel model of wireless signal in coal mine tunnels is established. The influences of the carrier frequency, propagation distance and the channel shape on the channel coherence bandwidth are analyzed and simulated, and the following conclusions are obtained： The coher- ence bandwidth increases with the increase of frequency, then tends to be constant; and it reduces with the increase of the propagation distance, then tends to be cinstant; in rectangular tunnel, when the frequency is sure, with the in- creasing of the shape factor the coherence bandwidth increases first and then decreases, and reaches its maximum when the width is equal to the height; when the rectangular tunnel cross section area is sure, with increasing of the shape factor, the coherence bandwidth increases first and then decreases, reaches its maximum when the width is equal to the height.