Background

The northern primeval forest area of the Greater Khingan Mountains in Inner Mongolia is one of my country's key forest areas, covering a total area of 106,000 square kilometers. It is vast, with complex terrain, and winter temperatures consistently below -40 degrees Celsius. Due to its remote location, much of the area is uninhabited and has long been a communication dead zone. In the event of a forest fire, effective communication between the fire front and the command center is impossible, severely impacting rescue efficiency and posing a significant threat to the lives of frontline firefighters.

To solve this problem, a Mobile Ad Hoc Network emergency communication system was introduced, constructing a wireless communication network covering the entire forest area. This project, spanning seven years, built 160 wireless self-organizing network base stations, achieving full wireless coverage across 106,000 square kilometers, becoming the world's first large-scale dedicated communication network for rescue command.

Challenges

• Extremely cold environment: Temperatures as low as -40 degrees Celsius, ordinary equipment cannot operate normally.
• Complex terrain: High mountains and dense forests easily block signals, making coverage difficult.
• Wide uninhabited areas: No roads, no electricity, no network, resulting in high construction and transportation costs.
• Power supply difficulties: No mains power available, relying on solar power, which is insufficient in winter.
• Signal attenuation: Dense forests affect wireless transmission, leading to unstable communication with handheld terminals.
• Equipment transportation difficulties: Supplies rely on human, animal, or helicopter transport, resulting in long lead times and high costs.
• Inconvenient maintenance: Heavy snow closes mountain passes for six months, making timely on-site repairs difficult.
• Remote monitoring difficulties: Scattered sites require the establishment of an efficient remote operation and maintenance system.

Solution

1. Network Architecture: Decentralized Wireless Networking This system adopts a wireless mesh architecture, independent of traditional base stations or fiber optic transmission. Each base station is both a signal transmitter and a relay node, allowing data to automatically hop between base stations. This interconnected approach gives the network the following characteristics: Self-organization: Base stations automatically discover surrounding nodes after powering on, dynamically forming a network. Self-healing: When a base station fails or its signal is interrupted, data automatically reroutes along alternative paths, without affecting overall communication. Multi-hop transmission: Signals can be relayed through multiple base stations, overcoming terrain limitations and achieving ultra-long-distance coverage. Big coverage: The entire network covers 106,000 square kilometers, deploying 160 units Defensor-BL8 solar powered base stations, forming a "Extendable Communication Network" covering the entire forest area.

2. Equipment Deployment: Scientific Site Selection Based on Local Conditions

Base station site selection follows the principles of "high ground, long reach, and priority for key points":

• High Ground Priority: Base stations are mostly located on mountain tops, ridges, and other locations with open views to maximize the coverage area of a single station. The "Changliang Beishan Data Collection Station 1200" in the legend is a key node at a high altitude.
• Key Area Densification: Appropriately densify base stations in high-risk fire zones, patrol routes, and key fire-prone areas to ensure seamless communication.
• Unmanned Area Station Deployment: The hundreds of kilometers of unmanned area to the north, formerly a communication blind spot, have had their signal coverage extended by deploying solar-powered, remotely maintained, unattended base stations.

Operation and Maintenance Support: Remote Monitoring + Regular Inspections   To ensure long-term stable network operation, a comprehensive operation and maintenance support system has been established: Remote Monitoring Platform: A network management system is set up in the command center to monitor the operating status, signal strength, and power supply of each base station in real time, automatically issuing alarms upon detecting problems. Tiered Response Mechanism: General faults are handled remotely; hardware faults are replaced on-site by professional personnel carrying spare parts, ensuring rapid recovery. Regular Inspections and Maintenance: Technical personnel are organized annually to conduct inspections in the mountains, checking equipment operation, cleaning solar panels, reinforcing antennas, etc., to ensure the equipment is in good condition.

Benefits

• First, it ensures effective firefighting command and dispatch. Since its establishment, the system has been used to command and dispatch hundreds of firefighting missions. During a fire, frontline firefighters can use handheld terminals to report real-time information such as the fire's location, its spread, and personnel positions. The command center can then scientifically allocate teams and resources, significantly improving firefighting efficiency.
• Second, it enhances the efficiency of daily patrols. During routine patrols, patrol personnel can maintain constant contact with headquarters through the system, reporting patrol progress and promptly reporting any abnormalities. This has changed the previous situation of "losing contact once entering the mountains," significantly improving both the safety and efficiency of patrol work.
• Third, it fills communication gaps. The northern forest area, stretching for hundreds of kilometers and previously uninhabited, has been a communication dead zone. This system has completely changed this situation, providing reliable communication support for forest management and emergency rescue, and has been highly praised by frontline commanders.