Communication performance study

Abstract

Wireless sensor networks (WSNs) applications are characterised by different requirements in terms of reliability and timeliness of the information to be delivered. It is of fundamental importance to develop efficient sensor technologies that can meet the requirements of the desired applications. In this chapter we investigate through experimental measurements the performance that can be achieved by two well-known technologies: Mica2 (Mica2 2002) and MicaZ (MicaZ 2004) sensors. Our work furthers the existing studies on motes communication by (i) considering both the Mica2 and MicaZ technologies, (ii) conducting different experiments with stationary and mobile sensors, (iii) developing a measurement framework to collect and analyse large amounts of empirical data. More specifically, our objective is to get a better understanding of the actual behaviour of Mica2 and MicaZ sensors, as well as of the quality of the communication links. The insights that we provide help in identifying which application requirements can be satisfied (and under which conditions), and in designing protocols at the higher layers that mitigate the inefficiencies of the sensor nodes. To derive meaningful results in spite of the difficulties in conducting empirical measurement, we developed a measurement framework and followed a rigorous methodology in the experimental setup. We focus on the performance metrics that better enable us to understand and characterise the communication dynamics in sensor networks, that is: packet loss probability and average length of a packet loss burst. Furthermore, we carry out experiments under some set-ups that help most in highlighting the effects of channel conditions and interfering transmissions. We hope that the description of the methodology used for our experiments and the measurement tool that we developed can be useful to other researchers..:. © Springer-Verlag Berlin Heidelberg 2007.