Improving data centric storage with diffuse caching in wireless sensor networks

In a sensor network that adopts data-centric storage (DCS), information of the same kind is kept in the same set of nodes. That is, when a sensor detects a certain event, no matter where it is, it sends the information to the designated location. When another node wants the information, it can send a query to that location to retrieve it. Unfortunately, existing protocols based on DCS are prone to the hot-spot problem where some nodes have to handle lots of messages. In this paper, we study how to apply diffuse caching on top of DCS. We diffuse popular information to other nodes so as to share the workloads. Our diffusing mechanism is adaptive that the distribution varies based on the popularity of the event type. We evaluate our protocol using simulations and the results Show that our protocol successfully alleviates the hot-spot problem and reduces the message overheads. Copyright (c) 2008 John Wiley & Sons, Ltd.