Veículos aéreos não tripulados como sorvedouro móvel em redes de sensores sem fio: investigando os efeitos do planejamento de rota na eficiência da rede

Abstract

Wireless sensor networks (WSNs) have been applied in the most diverse application domains. The performance of these networks depends directly on the network coverage as well as the battery charge of its sensor nodes, since discharged nodes cause gaps in the network. The battery discharge from the sensor nodes occurs mainly due to the transmission of messages and the processing of events in reactive networks, and will define the network lifetime. For this reason, the concern with energy consumption has motivated researches and the proposal of techniques to reduce the consumption of the sensor nodes. Some of these techniques employ the use of mobile instead of static sinks in order to avoid sending multi-hop messages over the network and, thus, reduce the energy consumption of the nodes resulting from the transmission of messages. As a mobile sink, an unmanned aerial vehicle (UAV) is usually used to fly over and collect events from the sensor nodes. Planning the route of the mobile sink is essential to ensure data collection and a good response time to events captured by the network. In this work, the impact of the use of a UAV as a data collector on the lifetime and coverage of wireless sensor networks is investigated, comparing the WSN with the mobile sink considering the zigzag and spiral route planning, with the WSN employing multi-hop and a static sink. In this comparison, different network densities were evaluated, as well as different proportions between the energy costs associated with communication and computing. In all the experiments carried out, the network with mobile sink, whether with zig-zag or spiral route planning, surpassed the standard WSN with fixed sink. The results showed that the mobile spiral sink captured more events than the zigzag sink. Regarding the network lifetime, the networks with a mobile sink employing a spiral route and a zigzag route did not show statistically significant differences. However, the use of the mobile sink independent of the used route planning made the network survive longer than the one with a fixed sink.