Concept for an Adaptive Low Power Wide Area (LPWA) Bat Communication Network

The communication of sensor networks enables a variety of different applications. Thus, technologies for connecting sensor nodes have gained comprehensive popularity over the last few years. Concepts like the Internet of Things (IoT) or Machine-to-Machine-Communication (M2M) incorporate the idea of a widespread data exchange among numerous items of various forms. In an interdisciplinary team we are extending this idea of sensor networking to the scope of wildlife tracking, in particular the tracking of bats. For this purpose, a large number of lightweight Ultra Low Power (ULP) sensor nodes are attached on the back of the animals. With a weight of just 1.8 g in total and a maximal equivalent isotropically radiated power (EIRP) of only 5 dBm, those sensor nodes are still capable to transmit data over a range of even more than 5 km. Adaptable bi-directional transmission schemes, not only between bat nodes, but also to a system of distributed base stations, conduced for gathering sensor data and localization, are implemented. This paper presents the conceptual and technical challenges in communication as well as a structural description of our base station network. Approaches toward an increase in the tracking range by means of an adaptive Low Power Wide Area (LPWA) telemetry system are presented. Finally, reasonable waveforms are evaluated, aiming at robust transmissions under the present conditions. Environmental effects and channel characteristics inferred by propagation models as well as hardware restrictions have to be taken into account.