The Impact of Diverse Execution Strategies on Incremental Code Updates for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) may require code updates for a variety of reasons, such as fixing bugs, closing security holes or extending functionality. WSNs typically have limited resources available and wireless updates are costly in terms of energy and can lead to early battery failure. The idea of incremental code updates is to conserve energy by reusing the existing code image on the node and disseminating only a delta file that is generated by differencing algorithms, which can be used to reconstruct the new image. Beyond these differencing algorithms, there are other strategies to minimize the delta, e.g., reconstructing only the changed parts of the image. This paper points out possible implications of diverse execution strategies and gives suggestions. In addition to the usual delta size, the impact on the flash memory was considered. The presented results can be used to select a fitting strategy for a given use case.