Abstract: To meet the communication requirements of future intelligent mines for high efficiency, low power consumption, low latency, and high bandwidth, the study proposes to apply the reconfigurable intelligent surface (RIS) assisted non-orthogonal multiple access (NOMA) technology to mine tunnel communication. The RIS is installed at the corner of the tunnel, and a large number of low-cost passive reflection units (RUs) are used to achieve reliable non-line-of-sight transmission of signals, simultaneously improving system spectral efficiency and transmission reliability based on NOMA multi user transmission. The study considers practical scenarios and establishes a RIS-NOMA mine communication system model based on wireless fidelity (WiFi) noise interference. From the perspective of outage probability, the transmission reliability of the system is analyzed. Based on probability theory, closed form expressions for outage probability of users located in different vertical distribution walls of the mine are derived, and the overall transmission efficiency of the system is analyzed using normalized measurement. The analysis and simulation results both indicate that: 1) The main factors affecting system performance include the number of RUs in RIS, the signal-to-noise ratio sent, the target data rate, the position of terminal devices in the tunnel, and the signal-to-noise ratio transmitted by noise; 2)Compared with traditional NOMA systems and collaborative NOMA systems, using RIS assisted NOMA systems in tunnel environments can better improve the communication performance of devices.

Key words: mine communication, reconfigurable intelligent surface, non-orthogonal multiple access; outage probability