An integral flow-based energy-efficient routing algorithm for wireless sensor networks

Sensor networks consist of a large number of sensor nodes performing distributed sensing and event detection. As sensor nodes are energy-constrained, energy-efficient routing is essential for increasing the lifetime of a sensor network. In Gandham, SR et al. (2003), we proposed an ILP-based method for routing in sensor networks with multiple mobile base stations. The ILP-based method does not guarantee integral routes and bounds on running time. In this paper, we consider static base stations and propose an algorithmic approach to obtain integral energy-efficient routes. We propose to split the lifetime of a sensor network into equal periods of time referred to as rounds and model the energy constrained routing during a round as polynomial-time solvable flow problems. The flow information from an optimum solution to a flow problem is then used as a basis for an energy-efficient routing protocol. Through simulations, we demonstrate that our routing algorithm performs significantly better than the shortest path based algorithms and consumes less energy than the ILP-based method. In addition, we present an algorithm to determine, a priori, lower bound on the lifetime of the sensor network.