Integration of a Mobile Node into a Hybrid Wireless Sensor Network for Urban Environments

Abstract

Robots, or in general, intelligent vehicles, require large amounts of data to adapt their behavior to the environment and achieve their goals. When their missions take place in large areas, using additional information to that gathered by the onboard sensors frequently offers a more efficient solution of the problem. The emergence of Cyber-Physical Systems and Cloud computing allows this approach, but integration of sensory information, and its effective availability for the robots or vehicles is challenging. This paper addresses the development and implementation of a modular mobile node of a Wireless Sensor Network (WSN), designed to be mounted onboard vehicles, and capable of using different sensors according to mission needs. The mobile node is integrated with an existing static network, transforming it into a Hybrid Wireless Sensor Network (H-WSN), and adding flexibility and range to it. The integration is achieved without the need for multi-hop routing. A database holds the data acquired by both mobile and static nodes, allowing access in real-time to the gathered information. A Human–Machine Interface (HMI) presents this information to users. Finally, the system is tested in real urban scenarios in a use-case of measurement of gas levels.

Development and Implementation of a Hybrid Wireless Sensor Network of Low Power and Long Range for Urban Environments

“…This way, it is intended to arrange the static gateways up around the city in a useful serving way. On the other hand, a previous work provided a working solution to the problem in the same city [ 68 ]. That work, based on Zigbee technology, is used as a baseline to compare results and to verify any improvements of using LoRa in this scenario.…”

“…That work, based on Zigbee technology, is used as a baseline to compare results and to verify any improvements of using LoRa in this scenario. For this purpose, the vehicle has followed the same route that in [ 68 ].…”

“…As mentioned earlier, the goal is to test LoRa technology in an urban environment. A previous work, providing a solution based on Zigbee [ 68 ] is used as a baseline to compare results of the proposed system, as well as to verify any improvements in this scenario.…”

“…In this way, it is possible to establish which zones of the city are white, which means that they are not covered by the mobile node, nor by the static concentrator nodes located at high points around the city. To listen to data packets from sensors embarked on the vehicle to compare the range and to count the dataframes acquired by the LoRa gateway with respect to the Zigbee gateway used in [ 68 ], since both of them have been driven along the same route. In addition, this allows us to analyze the behavior of a LoRa gateway in motion, at normal urban traffic speeds.…”

“…To listen to data packets from sensors embarked on the vehicle to compare the range and to count the dataframes acquired by the LoRa gateway with respect to the Zigbee gateway used in [ 68 ], since both of them have been driven along the same route. In addition, this allows us to analyze the behavior of a LoRa gateway in motion, at normal urban traffic speeds.…”