Reliable Cooperative Information Storage in Wireless Sensor Networks

Reliable data retrieval from a sensor network can require a temporal distributed data storage of the measured data among all motes. This is the case when a sink of information, or a gateway, is only occasionally present in the network. We consider a network consisting of a set of motes that in order to save energy independently of each other go into offline mode, switching theirs radios off. We propose a cooperative mechanism for distributed data storage that allows complete data retrieval with high probability. Reliable data retrieval is crucial for data-critical applications. Reliability is achieved by introducing redundancy in the system by applying Reed-Solomon scheme for data encoding. This solution can tolerate the situation where a certain number of devices in the sensor cluster is unavailable at the moment of information retrieval. A probabilistic analytical model is developed to investigate the performance of the proposed algorithm. This model is verified by simulation and prototype testing. Prototyping is done on the OpenSensor platform developed at Aalborg University. Performance results indicate that the proposed cooperative data distribution method outperforms the non-cooperative one.