Energy efficient routing with delay guarantee for sensor networks

The paper presents a routing algorithm that maximizes the lifetime of a sensor network in which all data packets are destined to a single collection node. Lifetime is maximized by adjusting the number of packets traversing each node. The adjustment is carried out by transmitting over alternative routes. First part of the paper assumes that the worst case delay resulting from energy efficient routing is less than the maximum tolerable value. Ignoring the delay constraint of the network, the routes are selected as the solution to a linear programming (LP) problem in which the objective is to maximize the minimum lifetime of each node. The solution is first implemented in a centralized algorithm. The LP solution is then approximated by an iterative algorithm based on least cost path routing, in which each step is implemented efficiently in a distributed manner. Second part of the paper incorporates delay guarantee into energy efficient routing by limiting the length of the routing paths from each sensor node to the collection node. Simulations reveal that the lifetime of the network increases significantly by optimal routing and there is not always a tradeoff between the delay guarantee and the battery lifetime of the sensor network. The delay of the network keeps increasing as the maximum allowed delay value increases although the optimal lifetime and the connectivity of all the nodes to the collection node is achieved so including delay constraint in energy efficient routing improves the network performance.