Wireless sensor gathering data during long time

A key characteristic of wireless sensor is the use of low-performance devices with limited resources. Certain applications, however, needs a large amount of data to be managed and stored. If the data should be continuously collected during a given period, its amount can become very large, which calls for efficient methods for handling them. Although the change of environmental information that is periodically collected by the sensor can sometimes be abrupt, there are cases where it is rather constant. In such cases, setting a value and storing the deviation of the data from this can be more efficient than storing the actual collected data. Of course, accuracy of the information is crucial. In this paper, we have proposed bit-vector based information storage method (BV) for this purpose. The method reduces the amount of overall data by storing only the deviation from the previous measurement as bit-value. However, the amount of data will still increase even if BV method is used, and we have also proposed the method for reducing this further at the expense of accuracy of old data. We have implemented a simulator to evaluate the efficiency of the proposed methods, and the methods turned out to be fairly efficient compared to normal cases.