900 MHz无线电波在地下长壁煤矿的传播

给出了900MHz无线电波在两个地下煤矿采煤工作区的测量结果,并有混合传播模型解释以上结果,得到的结论为：在巷道中,传播区域被转折点分为两段,在转折点前面,接收信号电平在42m内下降27dB;而在转折点之后,接收信号电平下降得很缓慢,胶带巷道和车辆巷道中衰减分别为13．3dB/100m,(6.75＋10)dB/100m,在采煤区进风巷中,传播损耗为22dB/100m,标准偏差为1．75dB;在采煤区长壁工作面上,传播衰减率均为75dB/100m,标准偏差小于2.2dB,在井下可以采用微蜂窝无线通信系统。

Radio propagation at 900 MHz in underground coal mines

In this paper, the results of radio propagation losses at 900 MHz in two underground longwall coal mines were summarized. A hybrid tunnel propagation model was used to explain the propagation characteristics in the passageways, correlated with the distance between the transmitter and the receiver in the passageways. In the passageways,two propagation regions separated by a breakpoint were observed. The breakpoints in the passageways were found to be 45 m from the transmitter. In the passageways the measured propagation losses before the breakpoint are all around 27 dB over the distance of 42 m. The propagation losses in the passageways after the breakpoint are much lower. They are about 13 3 dB/100m in the belt passageway and 6 75 dB/100 m plus 10 dB additional loss in the trolley passageway. In the headgate entry of the mining area, the propagation loss is 22 dB/100 m with the standard deviation of 1 75 dB. In the longwall faces of the mining area, the measured propagation losses are 75 dB/100m, the standard deviations do not exceed 2 2 dB. The additional loss due to obstructions by bents and common longwall coal mining equipment was also measured. Based on these results and from the propagation perspective, we believe that microcellular radio communications systems like CT2 Plus are feasible in coal mines.