Wireless radio technology to protect lone workers

People working alone are at particular risk of falling victim to workplace accidents. Therefore, it is essential that they are protected by systems that automatically detect threats such as fall hazards, potential medical emergencies or time spent in critical areas, and notify first responders or trigger warnings in appropriate areas.

The systems that are currently in use are not capable of performing these tasks adequately. Wireless systems in particular have limitations in terms of real-time capability or range. Radio communication experts from the Fraunhofer Institute for Integrated Circuits IIS are now working with Swissphone Wireless to develop wireless lone worker protection with an integrated area alerting system.

The radio-based alerting and emergency call systems currently in use are often limited when it comes to range and latency. Both of these factors can be crucial in an emergency, as they allow information and assistance to be sent quickly and effectively to the required location.

“A major issue is radio interference caused by other radio systems, which hinders transmission,” said Ferdinand Kemeth, researcher and group manager at the Fraunhofer IIS Positioning and Networks research area. “People working in hazardous areas or alone, however, must be able to rely on technologies such as wireless alarm systems no matter what.”

Similarly, alternative technologies to mobile communications such as Bluetooth, Wi-Fi or DECT only offer a limited communication range. According to Kemeth, “None of these technologies are capable of providing coverage for large buildings or areas without installing costly network infrastructure first.”

Together with Swissphone Wireless, Kemeth and a team of radio communication experts from Fraunhofer IIS are working on an emergency system for lone workers that is as fast as it is reliable. As part of the ‘was4wos: Wireless Alerting System for Worker Safety’ project funded by the German Federal Ministry of Education and Research (BMBF), the researchers are developing robust, customised radio technology for a reliable emergency alerting system. Their solution is a low power wide area network (LPWAN) connection based on the mioty radio protocol, which was developed by Fraunhofer IIS to set new standards in the field of wireless data transmission in terms of scalability, cost-efficiency, range, transmission reliability and battery life.

“By expanding this radio protocol, we hope to open up new applications such as lone worker protection,” Kemeth said. “In such situations, there are defined guidelines as to when the alarm should be triggered. We want to meet these guidelines by achieving the lowest possible latency in transmission — both from the sensor, for example a fall sensor or alarm button, to the infrastructure, and from the infrastructure to the first responders, who are then alerted immediately by their pagers.”

Real-time transmission and extensive range

Two important requirements, namely real-time transmission and extensive range, can be fulfilled by integrating mioty radio technology into the emergency alarm chains of lone workers. Kemeth explained, “The special telegram splitting transmission method used in the mioty protocol ensures that the message is transmitted reliably even when 50% of the message fails, as well as when there is interference from other radio systems or complex, reflective structures that you might find in industrial premises or halls or in rooms with limited network coverage, such as basements.”

The Class B and Class C variants of the mioty LPWAN protocol offer further benefits; it is possible to connect a large number of sensors (in extreme cases up to 100,000) using just one base station. Not only can messages be sent to the base station, but the events that occur in the opposite direction — ie, wireless alerts or operations — can be executed simultaneously using the same system.

“This is particularly appealing in places where no mobile communications infrastructure is available, and several kilometres need to be bridged first,” Kemeth said. “Using mioty, the distance to the next base station can be up to 15 km.”

Greater safety in industrial environments

Wireless communication and positioning systems that use mioty can be an effective solution in industrial environments. After all, the wirelessly networked, energy-efficient or energy-autonomous sensors and actuators operate robustly even in challenging environments.

“The sensors can also be deployed in highly metallic environments with many reflections and in environments where there is a lack of radio coverage,” Kemeth said. “We use energy harvesting to ensure that the sensors operate autonomously, meaning that small amounts of electrical energy are generated from sources such as ambient temperature, vibrations or light. As a result, the sensors are remarkably energy-efficient.”

The radio technology offers considerable advantages for all first responders, especially in industrial environments. When combined with radio-based positioning that is as accurate as can be, these technologies should significantly improve lone worker protection.

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