The University of British Columbia

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 separated parts of a partitioned WSN. In this paper, we propose a tree-based MF algorithm (TMFA), in which minimum-weight spanning trees of each partition of the WSN are evaluated with different alternate root nodes. Appropriate choice of the weights allows overall energy consumption or delay to be minimized. Two kinds of tree-constructing algorithms respectively named least energy tree (LET) and minimum hop tree (MHT) are presented and evaluated by deriving an energy model. For comparison, minimum spanning tree (MST) at a single root node and one level tree (OLT) that maximizes the use of the MF are considered. Simulation experiments show that LET and MHT outperform both MST and OLT when we take the message ferrypsilas moving cost into account.