Wireless Sensor Networks

The general context for Wireless Sensor Networks (WSNs) is small, cheap devices whose primary function is data acquisition, with communications capabilities enabling them to send data to a controller, using a wireless multi-hop topology. As an example, a WSN deployed for environmen- tal monitoring might contain a set of temperature sensors, sending “notifications” to a central controller when the temperature exceeds certain thresholds. Compared to a network of wired sensors, WSNs offer the advantage of enabling mobility to sensors, as well as reducing cost and space requirements for the installation of cables.

The IETF has created the ROLL working group and chartered it to work on a routing protocol for constrained sensor networks. This routing protocol is denoted "Routing Protocol for Low Power and Lossy Networks" (RPL).


Java Implementation (JRPL)

RPL has been implemented in Java, similar to the Java implementation of OLSRv2. The implementation runs in NS2 using AgentJ and on real machines (Linux). A routing protocol written in Java has several advantages, in particular for research purposes, over the more commonly used C/C++:
  • it allows easy prototyping, since it is less error-prone (due to missing pointers, automatic memory management, garbage collection, etc.) and since many auxiliary classes are already contained in the Java distribution (e.g. lists, hash tables, tree maps),
  • it facilities adding extensions to the core implementation due to class heritage,
  • it allows integration of tools as Java applets, also distributed on web pages, and
  • it is platform independent.

Publications

  • U. Herberg, T. Clausen, "Study of Multipoint-to-Point and Broadcast Traffic Performance in the 'IPv6 Routing Protocol for Low Power and Lossy Networks' (RPL)", accepted for the Journal of Ambient Intelligence and Humanized Computing, Springer, 2011
  • T. Clausen, U. Herberg, "Comparative Study of RPL-Enabled Optimized Broadcast in Wireless Sensor Networks", Proceedings of the 6th International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP), December 2010
  • T. Clausen, U. Herberg, "Multipoint-to-Point and Broadcast in RPL", Proceedings of the 1st International Symposium on Frontiers in Ubiquitous Computing, Networking and Applications (NeoFUSION), September 2010

Research Reports