applied sciences  
Modeling and Optimization of Wireless Signal Transmission Characteristics of Mine Roadway Based on 3D Ray-Tracing Method  
**[PERSON] 1**, [PERSON] 2,*(c), [PERSON] 3, [PERSON] 2, [PERSON] 2, [PERSON] 1,4,* and [PERSON] 2  
1 School of Mechanical and Equipment Engineering, Hebei University of Engineering, Handan 056038, China; [EMAIL_ADDRESS]  
2 Key Laboratory of Saline Lake Resources and Environment (Ministry of Natural Resources), Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China; [EMAIL_ADDRESS] (Z.N. ); [EMAIL_ADDRESS] (Q.W. ); [EMAIL_ADDRESS] (M.Z.) 3 School of Mining and Geomatics Engineering, Hebei University of Engineering, Handan 056038, China; [EMAIL_ADDRESS]  
4 Collaborative Innovation Center for Modern Equipment Manufacturing of Jinan New Area (Hebei), Handan 056038, China  
* Correspondence: [EMAIL_ADDRESS] (T.D. ); [EMAIL_ADDRESS] (Y.S. ); Tel. : +86-10-6899-2231 (T.D.) **Citation:** [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Modeling and Optimization of Wireless Signal Transmission Characteristics of Mine Roadway Based on 3D Ray-Tracing Method. _Appl. Sci._**2024**, 14, 1534. [[https://doi.org/10.3390/appl401534](https://doi.org/10.3390/appl401534)]([https://doi.org/10.3390/appl401534](https://doi.org/10.3390/appl401534))  
Received: 16 January 2024  
Received: 4 February 2024  
Accepted: 7 February 2024  
Published: 14 February 2024  
**Copyright**\(\copy\) 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([[https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)]([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/))). **1. Introduction**  
Coal is the primary source of energy worldwide and plays a crucial role in industrial production [1, 2]. To ensure safe production, efficient management, and emergency response in coal mines, it is of great significance to establish a reliable and efficient underground communication system [3, 4, 5]. The establishment of a safe and reliable wireless communication system in the limited space of coal mine tunnels is a hot research topic in coal production. At present, most mine communication and coordination systems use wired production dispatch communication systems, pager systems, low-frequency leak communication systems (60 MHz, 80 MHz, and 150 MHz), amplification broadcast systems used at the working face, as well as communication products based on Wi-Fi, WiMAX, and SCDMA technologies [6; 7; 8; 9; 10]. However, the wired communication is installed at fixed locations, while most workers perform dynamic operations. In the event of a mine disaster requiring communication and coordination, leaks often occur, and pager systems have the disadvantage of unstable signals, making it difficult for them to serve as an emergency communication tool. This prevents employees in danger from receiving evacuation information in a timely manner and evacuating promptly. As for the low-frequency leakage communication at 60 MHz, 80 MHz, and 150 MHz, due to the special underground environment, the use of a large number of frequency converters, the operation of overhead line locomotives, and the operation of high-power motors generate electromagnetic interference, resulting in poor call quality, loud noise, excessive interference, and high failure rates. They are not suitable for daily production scheduling communication and coordination in mines [11; 12]. Communication products based on Wi-Fi, wimax, and SCDMA technologies are civilian products introduced for underground use and are not industrial-specific communication systems [13; 14; 15].