Changing the game: long-range Wi-Fi networks set for mining rollout

In the final days of 2021, the University of Sydney proclaimed: “In a boon for the mining industry and internet users everywhere, University of Sydney telecommunications researchers are developing a safe and cost-effective technology that could be a wireless internet game-changer.” It was, they added, an industrial long-range high-speed Wi-Fi (LRWi-Fi) system that could transmit signals to hard-to-reach places while maintaining high data rates. 

This process could dramatically affect communication in mining, especially in underground environments. Technological innovation is nothing new to the sector – automation and advanced machinery are simply part of many mining sites – but processes typically considered suitable for commercial applications, such as connected devices and cloud storage, could have a role in the mining industry. 

Now, more than a year on from the university’s initial announcement, questions remain as to the status of the technology, and the feasibility of its use in mining. With considerable potential for this technology in particular, and the process being something of a proving ground for connected devices in mining more generally, the future could be bright for underground communications and connectivity.

Professor Yonghui Li: A broadband wireless communication network is an essential infrastructure for digitalising underground mining. It enables the real-time continuous tracking of workers, machines and assets, emergency and evacuation [situations], zone management and remote control. It ensures worker safety, increases mine efficiency, productivity and connectivity, and brings many other benefits. However, key risks are to worker safety, the impact on mines’ operations, efficiency and productivity.  

Therefore, there is growing unmet customer need for cost-effective LRWi-Fi networks across multiple industries. Existing Wi-Fi systems have been designed for indoor applications, with a short communication range of less than 100m. To deploy these systems in large areas, such as underground mines, is expensive and often the signal quality is poor. So, most mines can only deploy Wi-Fi in very limited areas.

Professor Yonghui Li: In principle, a long communication range can be achieved by using directional antennas, which particularly fit underground mines because the radio propagation in a tunnel is almost unidirectional. Current Wi-Fi systems use carrier-sense multiple access (CSMA) protocols, which cannot be used with directional antennas as they cause serious hidden node problems in long-range transmissions, leading to frequent signal collisions and transmission failure.  

We developed a novel centralised multiple access protocol stack for Wi-Fi systems based on commercial chipsets. In our protocol, the access point (AP) allocates a dedicated channel so medium transmission is guaranteed to be available and signal collisions are eliminated. Secondly, conventional Wi-Fi uses a distributed CSMA/collision avoidance Wi-Fi access protocol, which has a random and unpredictable delay and low reliability. 

Our proposed centralised access protocol exploits [the] novel fine quality of service control algorithms and optimises the resource and rate control among different devices; it can achieve a low and deterministic latency, essential for mission critical applications.

Professor Yonghui Li: There are four competing technologies for long-range wireless communications: a mesh Wi-Fi network; Wi-Fi terminals with directional antennas; Wi-Fi HaLow; and LoRa. We only compare [to] the first two technologies because Wi-Fi HaLow and LoRa are designed for low-rate applications.  

In mesh networks, Wi-Fi nodes cooperate with each other and relay a packet from node-to-node until it reaches its destination. Mesh Wi-Fi requires a large number of Wi-Fi APs and gateways. Therefore, it is still costly for network deployment.   

Existing Wi-Fi technologies with directional antenna are designed for fixed long-range communication for outdoor Wi-Fi backhaul applications. Both the transmitter AP and terminals are equipped with directional antennas, which must accurately be aligned before transmission. Devices have to be installed at fixed locations and cannot be used for mobile devices. This technology is not compatible with existing Wi-Fi devices. The device requires specific equipment with directional antennas, which can be costly and large, and thus cannot be integrated with mining equipment such as helmet lamps. 

Our Wi-Fi devices use omnidirectional antennas. Its size is very small and can easily be integrated with mining equipment. The system is compatible with existing Wi-Fi technologies, which is critical as they are already deployed Wi-Fi infrastructures in underground mines.

Professor Yonghui Li: The competitive advantage of our solution is low cost, significantly increased coverage and compatibility with the existing Wi-Fi devices. It is very expensive to use existing Wi-Fi systems to provide network connectivity over a large area as it requires a large number of Wi-Fi APs with power and network cable connections. Our LRWi-Fi systems can significantly increase the coverage area of the Wi-Fi Aps; the solution reduces the number of Wi-Fi APs for full network coverage and decreases the deployment cost, while maintaining a high transmission date rate.  

More importantly, LRWi-Fi is a commercial off-the-shelf Wi-Fi device compatible with the existing Wi-Fi protocol stack. This will be the world’s first LRWi-Fi system compatible with conventional Wi-Fi, supporting mobile and multiple access terminals. Existing Wi-Fi systems have random and high latency; our LRWi-Fi system, with centralised protocol, will achieve low and deterministic latency, essential for mission critical applications. Compared with existing directional antenna-based systems, our devices will use omnidirectional antennas.  

Also, our devices are very small and can easily be integrated with mining equipment, at a low cost. It’s compatible with existing long-range Wi-Fi communication solutions, critical as there are billions of dollars’ worth of Wi-Fi infrastructure already deployed in underground mines around the world. Finally, our Wi-Fi protocol stack will not only increase range, it will significantly reduce latency, increase data rate and improve reliability. 

Our technology offers a longer Wi-Fi range with lower installation costs. Our modelling of an active mine site demonstrated that we could reduce the number of APs from 63 to nine, lowering the overall cost by more than 80% in this scenario. It will also significantly improve the reliability and response time of safety and emergency procedures, essential for some of them most dangerous jobs in underground mining.

Professor Yonghui Li: We’re working with a mining equipment company, Roobuck, to manufacture LRWi-Fi APs. The system will be tested in mines in the coming months and commercial products will be available later this year.

There will be no need to replace existing infrastructure. If equipment already has integrated Wi-Fi devices, they can directly communicate with our Wi-Fi APs.