Safety-Critical Sensor Networks for Building Applications

The project focuses on (hard) dependability and real-time constraints in wireless sensor networks applied to a distributed wireless fire-alarm application. For sustainable operation it is crucial that the system exhibits very high dependability, small energy consumption and adherence to the stringent timing constraints required by the application. This will introduce to the domain of wireless sensor networks yet unavailable solutions to meet hard real-time constraints and performance guarantees as opposed to current dominating best-effort practices.

In particular, such a fire-alarm application (wireless and multi-hop) has the following characteristic:

• There is a hard time limit for an alarm message, i.e. a detected fire needs to be reported within a few seconds (e.g. 10).
• The nodes are battery powered. Nevertheless the power supply should last for a couple of years, requiring an ultra-low power consumption (i.e. a duty cycle of less than 1% is required).
• Alarm messages hardly ever occur. That is, the network always needs to be ready to forward an alarm (with minimized power consumption). However, in the rare case of an event, quiet a lot of energy can be spent in order to ensure a reliable notification.
• The nodes in the network must be monitored in order to check for failed nodes. There is a hard time limit (in the order of minutes) to detect such node failures.

There are various aspects that impact the application's performance:

• MAC protocol
  The underlying MAC protocol influences the energy consumption and the interference within the network.
• Routing
  A robust routing protocol is required to ensure a timely and reliable event notification.
• Initialization
  The initialization of the network might have a huge impact on the application's performance.
• Security/Jamming
  Jamming the network or triggering a false alarm must not be possible.

Further Information can be found on the home pages of the participating members: Andreas Meier, Mario Strasser.

This project is supported by the Swiss Confederation’s innovation promotion agency (CTI), the Swiss National Science Foundation SNF and NCCR-MICS.