| Summary: | The characteristics of the mine wireless relay emergency communication system are analyzed in this study. The wireless transmission power is limited by explosion-proof, the mine wireless transmission attenuation is large, and the wireless transmission distance is short. The working frequency band is not limited on the premise that the wireless communication equipment working underground does not interfere with each other and does not affect the normal operation of the wireless equipment on the ground when being taken out of the mine. The relay links are distributed in a chain in the roadway, and the overall network is in a tree topology. In order to solve the impact of the broken cable (cable or optical cable) caused by the coal mine accident on the mine emergency communication system, the implementation method of mine wireless relay emergency communication system is proposed. This method separates the data transmission link from the protocol control link to improve the flexibility of link control and the transmission efficiency of routing protocol signaling. The receiving/transmitting frequency bands and sub-channel frequencies of each base station in the link are set according to the physical sequence of base stations, which solves the problem of mutual interference between relay stations at all levels. In data link relay transmission, each relay station in the link can exchange data continuously with the front and back nodes, which solves the problems of bandwidth loss, relay delay and system stability caused by multi-level relay. The frequency molecular channel mode of the relay station with spatial multiplexing of zones solves the problem of limited frequency division channel resources. The fixed node-based transparent routing strategy simplifies the level-by-level route addressing and route discovery process and improves data forwarding efficiency. The redundant base station down-link routing strategy of normal link avoids the channel interference problem caused by the mixed transmission of primary and redundant nodes. The link breakpoint recovery method of redundant base stations, mobile terminal bridging and local access coordination improves the anti-fault ability of the link.
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