Energy-Efficient Data Dissemination for Wireless Sensor Networks

In order to disseminate a large amount of data through a sensor network, it is common to split the data into small-sized chunk packets. If the data is additionally encoded by a forward error correction (FEC) code, missed chunks can be recovered. Fountain codes are a special kind of FEC code which have the property that the sender provides the data in a virtually endless stream by combining original chunks at random. No matter which chunks get lost, each receiver only needs any k chunks from the stream. In broadcast scenarios, fountains have the additional advantage that only little redundancy is required, even if several receivers have missed different chunks. We will show the benefit of Fountain codes in wireless sensor networks in comparison to raw transmissions and other FEC codes. To support the actual data dissemination, we propose two generic distributed protocols: an acknowledgement-based and a request-based protocol. The evaluation is carried out in a real testbed consisting of 20 sensor nodes