Minimum energy fault tolerant sensor networks

We devise a scheme which can provide reliable transport services in sensor networks and give an algorithm which minimizes the energy use of our scheme. We use a distributed sink where information arrives at the sink via multiple proxy nodes, called "prongs" in this paper. The sender node uses forward error correction (FEC) erasure coding to encode each packet into multiple fragments and transmits the fragments to each of the prongs over a path which is disjoint from the paths to the other prongs. The erasure coding allows the sink to reconstruct the original packet even if some of the fragments are lost. We use a cross-layer design where higher network layers use information about packet loss and energy consumption to distribute the load in the network. We show that the source can distribute the load so that energy consumption is minimized. The optimization takes fault tolerance into account with a bound on the probability of packet loss. The extra fragments increase both the reliability and the energy in the network. However, we show with simulations that it is possible for the sensor to decrease energy use in the network by using the diversity available with multiple network paths.