Effelsberg “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 sce-narios, 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 Foun-tain codes in wireless sensor networks in comparison to raw transmissions and other FEC codes. To support the ac-tual 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. 1