Design of wireless Mesh communication system in coal mine

Abstract

The current wireless communication technology cannot meet the requirements of high throughput rate, long-distance transmission, flexible networking, and simple installation and deployment in the special space and variable working environment of coal mine. In order to solve the above problems, a wireless Mesh communication system in coal mine is designed. The distribution of wireless Mesh network nodes in a single roadway is proposed, and the system hardware and software design method is introduced. The network node is composed of baseband board and RF front-end. The baseband board mainly realizes digital waveform generation, supports embedded system management information interaction and automatic gain control of received signal. The RF front-end mainly achieves the function of amplifying RF signal intensity to the target power. The test results are listed as follows. ① When the RF front-end transmission gain is >17 dB, adjusting the transmission average output power of AD9361 software radio module can make the system average output power 37 dBm. ② The adjacent channel power ratio of the RF front-end transmission is <-43 dBc. ③ The insertion loss of the RF front-end receiving link is <1.8 dB and the transceiver switching time is <1 μs. ④ The average throughput rate of the system is ≥45 Mbit/s, which meets the requirement of no lag in monitoring video transmission in underground coal mines. ⑤ The call quality level is ≥3, indicating that the call is relatively clear in most working hours.

Keywords

• wireless communication in coal mines; wireless mesh network; mobile mesh network node; fixed mesh network node; rf signal; automatic gain control; time division duplex