Research and development of 5G communication system standards for coal mines

In order to meet the needs of remote monitoring, video monitoring, data acquisition, and voice communication in coal mines, the 5G communication system used in coal mines should have the following functions. ① The system has different service-bearing functions such as remote control, monitoring, positioning, surveillance, and voice. ② The system has remote control functions such as coal mining machines, roadheaders, electric shovels, excavators, trackless rubber wheeled vehicles, and electric locomotives. ③ The system has an emergency remote takeover function for mining transportation vehicles. ④ The system has a remote real-time transmission function of camera audio and video. ⑤ The system has data collection functions such as monitoring equipment, sensors, and vehicle-assisted driving. ⑥ The system has a voice call function. ⑦ The system has an end-to-end slicing function that meets the differentiated business performance requirements of remote control, monitoring, video, and voice. ⑧ The system supports SA networking and 5G NR communication system. ⑨ The system supports 5G LAN Ethernet communication. ⑩ The system has an emergency inertia operation function. In case of disconnection between the mining area's private network and the communication operator's public network, local businesses can continue to operate online. ⑪ The system has a device level redundancy protection function that ensures uninterrupted data service in the event of a single physical port failure. ⑫ The system has a dual device redundancy protection function of the core network that allows for the switching of backup devices to continue providing services when the main device fails. ⑬ The system has the core network control surface transmits confidentiality and integrity protection functions to ensure the security of the core network control surface. ⑭ The system has terminal authentication, checking, and restricting access to unauthorized terminals in the system, supporting the authentication of terminals by coal mining enterprise security servers. ⑮ The system has functions that prevent terminal attacks on the system and legitimate terminal. ⑯ The system has the integrated management function of the core network, transmission equipment, base station controller, base station, and terminal. ⑰ The system has a centralized monitoring function for network performance and business service performance. ⑱ The system has an abnormal visual alarm and fault location function. ⑲ The system has the evaluation function of mining 5G network resources. The system can evaluate the utilization rate of 5G network resources and provide a report on whether new services can be accessed when the coal mine adds new services or more terminals are connected to the 5G network. ⑳ The system has backup power supply. The main technical indicators of the 5G communication system used in coal mines should meet the following requirements. ① When the uplink rate is 20 Mbit/s and the wireless working frequency band is 700-900 MHz, the wireless coverage radius (unobstructed) of the base station in the underground coal mine should be ≥ 500 meters. When the wireless working frequency band is other working frequency bands, the wireless coverage radius (unobstructed) of the base station in the underground coal mine is ≥ 150 m. When the uplink rate is 30 Mbit/s, the wireless coverage radius (unobstructed) of the base station in the open-pit coal mine is ≥ 400 m. ② The wired transmission distance from the base station to the base station controller is ≥ 10 km. ③ The maximum number of access terminals in the system is ≥ 20000. ④ The wireless transmission power of the base station and terminal of the underground coal mine is ≤ 6 W. The transmission power of the base station in the open-pit coal mine is ≤ 320 W. The wireless transmission power of the terminal in the open-pit coal mine is ≤ 6 W. ⑤ The base station wireless reception sensitivity is ≤ −95 dBm. The terminal wireless reception sensitivity is ≤ −85 dBm. ⑥ The wireless working frequency should be selected from the frequency bands of 700 MHz, 800 MHz, 900 MHz, 1.9/2.1 GHz, 2.6 GHz, 3.3 GHz, 3.5 GHz, 4.9 GHz, 6 GHz, etc. (preferably 700 to 900 MHz for underground coal mine). ⑦ When the format is TDD and the frame structure is 1D3U1S, the average uplink throughput rate of multiple users accessed by the base station is ≥ 600 Mbit/s, and the average downlink throughput rate is ≥ 250 Mbit/s. ⑧ For underground coal mines, when operating upstream services at 1 Mbit/s and 20 Mbit/s, the average system delay should be less than 20 ms, and the probability of end-to-end delay stability being less than 100 ms should not be less than 99.99%. For open-pit coal mines, when operating upstream services at 1 Mbit/s and 30 Mbit/s, the average system delay should be less than 20 ms, and the probability of end-to-end delay stability being less than 100 ms should not be less than 99.9%. ⑨ The packet loss rate of a single user is ≤ 0.01%. ⑩ The handover delay for a single user from cell A of the base station to cell B of the base station is ≤ 100 ms. ⑪ The continuous working time of the mobile station battery should not be less than 11 hours, among which the call time should not be less than 2 hours. ⑫ After a power outage in the power grid, the backup power supply continuously provides power to the base station, base station controller, and transmission equipment for ≥ 4 hours.