Data-centric cooperative storage in wireless sensor network

Although commonly used sensor nodes are resource-limited devices, enabling cooperation among these devices can help building very powerful systems. Besides other characteristics, storage capabilities of individual sensor nodes have to be considered as this might be very small compared to the collected sensor data. The temporal availability of sink nodes or the importance of collected data are not equal for all nodes and, therefore, demand storage of the generated data locally for later retrieval. Furthermore, data items (detected events) may be collected at different rates, which can lead to hotspot-like storage requirements. In this paper, we introduce a data-centric cooperative storage mechanism for wireless senor networks. Our approach is based on Virtual Cord Protocol (VCP), a virtual relative position based efficient routing protocol that also provides means for data management, e.g. insert, get, delete, and replicate, as known from typical Distributed Hash Table (DHT) services. Data items are distributed deterministically over several nodes in the same vicinity. Thus, storing and retrieving data items typically require communication with local nodes. To maintain information about stored information, we use a bloom filter to track the nodes that are storing particular items.