Dennis van Doorn describes how a resilient IoT mesh network could deliver higher quality hospital care for less money and lower the pressure on human resources
Recently, a pilot project initiated by a Dutch children’s hospital enlisted an entire ward as an IoT ‘playground’ to experiment with various types of tag, sensor and switch in a network. The starting point is a network topology that provides high resilience and flexibility. It offers clear advantages over conventional mesh network technologies. It provides the ability to construct highly scalable, high-density networks.
Excellent radio wave interference resistance is ensured by using the 2.4GHz frequency band, in this case adopting a unique protocol that is different from wireless LAN or Bluetooth technology.
All intelligence is in the network. Devices decide the best actions by themselves, locally choosing how to make best use of the locally available radio spectrum and energy. No central network controller is needed. Local decision-making ensures that devices always operate in an optimised way, ensuring scalability for massive IoT applications.
Adaptive Multi-Hop Mesh Topology
Devices in the hospital mesh communicate data over multiple hops. Topology is optimised continuously, adapting to changes in the environment and the network. For each device there are multiple routing options, and multiple gateways can be used in the same network. Multiple connection directions are supported: to/from the cloud and device-to-device in the network.
With this type of mesh, devices automatically choose their role according to the situation. This means every device is a possible routing point for forwarding data. Users do not need to define the roles of the devices, as this is done autonomously. There are no repeaters, routers or other infrastructure devices required in this type of mesh. In this roll-out nodes include mobile tags for asset tracking, sensors for environment monitoring, such as temperature and C0₂, and to monitor hospital refrigerators such as those used to store medication. In addition, the mesh network accommodates devices for lighting control and indoor navigation.
Tracking & Sensors
The initial focus at Dutch hospital was for tracking hospital equipment. Beds, incubators and infusion pumps are among the many items that go missing, even in the best-run hospitals. Locating lost gear is a drain on staff time, distracting from the central task of patient care. IoT track/trace modules can be attached to anything. Location data can also be used for stock control, for example alerting staff when stocks are low. Sensors can alert staff to things such as the need for towel replenishment in washrooms, or liquid spilled on the floor.
By using the mesh network an unlimited amount of assets can be added or removed without network maintenance. Asset tags simply reroute the information. In addition, there is the option to use historical data to further optimise the flow of assets. Heatmap apps enable visualisation of congestion points, alerting to problem areas such as hallways.
Smart Lighting & Switches
Light is an important aspect in patient wellbeing and staff productivity, as well as responsible energy consumption. The IoT solution encompasses a connected, intelligent lighting system that combines low-latency operation for light control with the high data rate network to capture data from various sensors. Sensors capture key data about their surroundings, such as occupancy, motion and air quality. They can last for years within this network thanks to the ultra-low power mode of connected devices.
At the hospital, smart LED lighting fixtures act as anchor nodes in the mesh network, through which the battery-powered mobile tags communicate their positions. This solution proved no more expensive than a normal LED lighting upgrade. Being mains-powered, the lighting provides a very low latency network that makes it simple to extend the scope of IoT applications running on it.
By integrating energy-harvesting wireless switches, the energy produced by pressing the button is enough to make switch the light or make a call for assistance, a bed or any other function. As a bonus, the lighting offers extra functionality such as daylight compensation, smart grouping and lighting plans based on presence or personal preferences. Presence sensors provide occupancy data, enabling further efficiency savings.
Indoor Navigation Improvements
Guiding patients and staff is another significant challenge in large hospitals such as the Dutch children’s hospital. Navigation and wayfinding are currently offered through photo-based wayfinding. However, including beacons in the IoT mesh enables nodes to transmit standard Bluetooth beacon messages to indoor mapping and navigation apps. The mobile application gives users accurate positioning in real-time on their mobile phone, along with wayfinding and turn-by-turn navigation. For the hospital, this is just the start of the journey.
Dennis van Doorn is with Fujitsu