Pods: Issues in the Design of Practical Ad-Hoc Wireless Sensor Networks

The Pods ad-hoc wireless sensor network has been designed to study the environment of endangered species of plants. This paper presents the overall design of this network, focusing on the design of the network nodes and of the algorithms we use. In designing and building the Pods network, several issues have become apparent that are more widely applicable to sensor networks in general. Of these issues, the two most fundamental are scaling and energy efficiency. In the foreseeable future large sensor networks can and will be built, and any algorithms used must scale to many thousands of nodes and to networks with diameters of hundreds or thousands of hops. As such networks are built, energy efficiency becomes an essential element of both the overall cost and the ease of deployment. These two elements can therefore significantly affect the viability of a wireless sensor network design. Algorithms developed as part of the Pods project, particularly the MOR routing protocol, provide good performance on both of these measures.