Energy-efficient Tree-based Message Ferrying Routing Schemes for Wireless Sensor Networks

摘要

Wireless sensor networks (WSNs) are prone to partitioning due to limited energy in sensor nodes and unreliable radio communications between them. Message ferrying (MF) has been proposed as an effective means to deliver data between disjoint parts of a partitioned WSN. In this paper, we propose a tree-based MF algorithm (TMFA) with least ratio tree (LRT) construction in order to prolong the lifetime and reduce energy usage in a WSN employing MF routing. LRT constructs a spanning tree from the topology graph of each partition of the WSN by setting the weight of each edge in the graph as the ratio between the energy cost to deliver a packet over the corresponding wireless link and a linear combination of the residual energy of the transmitting and receiving nodes connected by the link. In addition, the root of the spanning tree is randomly chosen among the nodes in the partition with residual energy equal to or larger than the mean residual energy of all nodes in the partition, so that the energy of nodes are expended evenly. Experimental results show that, compared with the previously proposed Least Energy Tree (LET) and Minimum Spanning Tree (MST) construction methods for TMFA, LRT construction outperforms both the LET and the MST construction in network lifetime and in the ratio of the number of packets reaching the sink to the total energy expended by all the nodes.