Energy aware routing and Data Funneling in sensor networks

In this chapter we present a number of techniques to extend the lifetime of an energy-constrained sensor network. Defining the lifetime as the time it takes for the first node in the network to die, the presented protocols attempt to minimize the energy consumption of the network. Yet, at the same time the protocols may use sub-optimal paths so as to reduce the burden of routing on nodes that are depleted of energy. In particular, two approaches are discussed. The first scheme, energy aware routing is a probabilistic scheme which chooses paths based on the energy required for communication and the residual battery life on nodes. Simulation results show that it performs very well as compared to an optimal routing mechanism based on a centralized computation of routes. The second mechanism, called Data Funneling is a technique to aggregate data packets from sensors in a region so as to minimize the energy spent on packet headers. Depending on the size of the region, this scheme can provide substantial gains in networks where the data payload size is small, which is typical in sensor networks. Since it is an aggregation mechanism, it can also be used with source coding techniques for further performance improvements.