DATA GATHERING ALGORITHMS TO OPTIMIZE STABILITY-DELAY AND NODE-NETWORK LIFETIME FOR WIRELESS MOBILE SENSOR NETWORKS

摘要

We propose two distributed spanning tree-based data gathering algorithms for wireless mobile sensor networks wherein the topology dynamically changes with time. One of the two data gathering algorithms is designed to determine stable spanning trees that exist for a longer time, taking into consideration the predicted link expiration time (LET). However, stability-based data gathering leads to unfair use of certain nodes (the intermediate nodes of the tree that spend more energy compared to the leaf nodes) in the network, triggering premature node failures eventually leading to network failure (disconnection of the network of live nodes). In this context, we propose a minimum-distance spanning tree-based data gathering (MST-DG) algorithm that is more energy-efficient and prolongs both the node and network lifetimes at the cost of frequent tree reconfigurations. MST-DG trees have relatively fewer leaf nodes resulting in increased fairness of node usage. However, the larger height of the MST-DG trees contributes to a much longer delay per round of data gathering compared to the LET-DG trees. We thus observe a complex stability-delay vs. node-network lifetime tradeoff for data gathering in wireless mobile sensor networks, and this research is the first of its kind to identify such a tradeoff in this area.