Coal mines are areas where humans extract coal resources from coal rich mining areas, generally divided into underground coal mines and open-pit coal mines. When the coal seam is far from the surface, it is generally chosen to excavate underground tunnels to mine coal, which is called underground coal mine. When the coal seam is very close to the surface, it is generally chosen to directly strip the surface soil layer to excavate coal, which is an open-pit coal mine. The vast majority of coal mines in our country belong to underground coal mines. The scope of coal mines includes a large area of above ground, underground, and related facilities. Coal mines are reasonable spaces excavated by humans when excavating geological layers rich in coal, usually including tunnels, shafts, and mining faces. Coal is a very important raw material in China's national construction,

1、 User demand analysis

Users need to establish a wireless monitoring system during the construction process of coal mines to strengthen the supervision of safety operations and production in the mining area. Due to the complexity of the mining area, using wired methods may not be sufficient in some scenarios, so wireless devices are needed for system setup.

2、 Design of Wireless Transmission Scheme

The first requirement of the user is to have a moving video surveillance image inside the underground coal construction tunnel. The user needs to transmit this image to the ground end. The situation inside the underground coal mine tunnel is quite complex, so when choosing wireless devices, we consider using our company's low-frequency dedicated network MESH equipment for transmission. As shown in the following figure:

As shown above, the front-end mobile monitoring point is carried by personnel or vehicles and moves inside the tunnel. Due to the fact that the tunnel may not be straight and may have curved parts, a MESH self-organizing network device is placed at the turning point. The devices self network and transmit video signals to the tunnel shaft, and then transmit them to the ground through optical fibers or other devices.

The second requirement is video surveillance in the mining area. Many places in the mining area are equipped with surveillance cameras, which do not require wiring and use long-distance, high bandwidth wireless devices for transmission. The installation is simple and convenient, the construction period is short, and it can be reused. As shown in the following figure