Flash mob organization in heterogeneous wireless sensor networks

We present a synchronization algorithm that is able to let the nodes in a sensor network perform a certain task at a given point in time. In contrast to other time synchronization algorithms we do not provide a global time basis that is shared on all nodes. Instead, any node in the network can spontaneously initiate a process that allows the synchronous execution of arbitrary tasks. We show that our approach is advantageous in scenarios where a global time is not needed, because it requires little communication compared with other time synchronization algorithms. We also show that our algorithm works in heterogeneous systems where the hardware provides highly varying clock accuracies. Moreover, heterogeneity does not only affect the hardware, but also the communication channels. We deal with different connection types--from highly unreliable and fluctuative wireless channels to reliable and fast wired connections.