Long-range Wi-Fi to improve mine connectivity
An industrial Wi-Fi system could deliver long-range communication, high data rates and low latency potentially benefitting the mining industry.
Researchers at the Centre for Internet of Things (IoT) and Telecommunications at the University of Sydney, Australia, claim the system allows wireless signals to travel several kilometres, transmitting them to hard-to-reach places while carrying more data and avoiding drop-outs and lag.
It is said to be the first long-range, high-rate Wi-Fi system of its kind that is compatible with conventional Wi-Fi and supports both mobile and multiple-access terminals. It integrates new protocols with off-the-shelf Wi-Fi chips, allowing integration with existing infrastructure.
Project lead, Professor Yonghui Li, explains how existing Wi-Fi systems fall short of emerging applications in the IoT economy and 6G because their design favours indoor environments with a short transmission range of less than 100m.
Importantly, these systems have random and high latency, which creates a delay between the user’s action and the time it takes for the signal to be transmitted or reproduced. They also require a large number of access points (APs) and connecting power/network cables for connectivity over a large area, making them an expensive solution.
‘Our long-range Wi-Fi systems can significantly increase the coverage area of the Wi-Fi access points,’ Li says. ‘The solution can reduce the number of Wi-Fi access points for the full network coverage and decrease cost, while maintaining a high transmission data rate.’
The long communication range is achieved using directional antennae, which, Li explains, are ideal for underground mines that require remote monitoring of workers and control of sensitive mining equipment.
He notes that current systems use carrier-sense multiple access (CSMA) protocols, meaning they cannot be used with directional antennae as they cause ‘serious hidden node problems in long-range transmissions, leading to frequent signal collisions and transmission failure’.
To extend their coverage over large areas, existing systems rely on mesh networks, which are characterised by a high number of nodes and relay hops, making it expensive for large-area deployment.
Supported by an AUS$800,000 grant from the New South Wales Physical Sciences Fund, Australia, the new approach is integrated with a centralised time division multiple access (TDMA) protocol and also uses commercial off-the-shelf chipsets. TDMA protocol enables the AP to allocate a dedicated channel so the transmission medium is always available and the signal collisions are eliminated.
The system uses omnidirectional antennae, which provide 360o radiation patterns, enabling connectivity in all directions. As the size of the end devices are very small, Professor Li says they can be easily integrated with existing equipment at a low cost.
It also switches between the conventional CSMA protocol, albeit with collision avoidance, and the TDMA protocol.
‘Our proposed centralised access protocol exploits novel fine quality of service control algorithms and optimises the resource and rate control among different devices,’ Li explains. ‘It can achieve a low and deterministic latency, which is essential for mission-critical applications.’
Australian IoT firm Roobuck plans to manufacture and certify the system for commercial use in the next two years.
The team behind it also sees potential in real-time surveillance, image and data transmission, and in airports, shopping centres, university campuses, emergency services, large factories/warehouses, and industrial or agricultural settings, including video surveillance of crops and control of vehicles, tractors and robots on farms.
