Optimizing System Life time for Data Gathering in Networked Sensor Systems ∗

We focus on data gathering problems in energyconstrained networked sensor systems. The system operates in rounds where a subset of the sensors generate a specified number of data packets during each round. The goal is to maximize the system life time in terms of the number of rounds the system can operate before a node fails due to lack of energy. We show that the above problem reduces to a restricted flow problem with quota constraint, flow conservation requirement, and edge capacity constraint. We further develop a strongly polynomial time algorithm for this problem, which is guaranteed to find an optimal integer valued solution that specifies the number of data packets to be transferred between any two neighboring sensors for each round.