Fault-tolerant data storage in Wireless Sensor Networks

In Wireless Sensor Networks (WSNs), each node performs multiple roles, such as sensor, router, and storage. It gathers data from an environment and does not only transfer the data to destinations such as sinks but also store the data in its storage. Therefore, just one node failure can cause malfunctions of various facilities of a WSN. So far, many schemes are proposed to overcome such malfunctions, however, most of them give less consideration to storage-role of nodes, that is, to reserve data safely. Besides, even schemes paying attention to storage-role of nodes are based on impractical assumptions or are suitable to particular cases. In this paper, first, we investigate the data preserving methods of existing schemes and their limitations. Then, we suggest a backup scheme as a solution to overcome such limitations and considering factors for developing a new backup scheme. The considering factors include the followings; the number of backup data, the location of backup data, and data recovery method. Finally, we propose the backup scheme reflecting the considering factors. The proposed scheme can safely preserves data in spite of node failures and consumes reasonable energy. Furthermore, it is suitable well to common WSNs and does not need any impractical assumptions.