# Wireless Sensor Networks for Enabling Smart Production Lines in Industry 4.0  
[PERSON]  
1 Department of Information Technology, Ghent University/IMEC, 9052 Ghent, Belgium;  
[PERSON]ESS] (D.P. ); [PERSON]SS] (W.J.) 2  
[PERSON]  
1 Department of Information Technology, Ghent University/IMEC, 9052 Ghent, Belgium;  
[PERSON]ESS] (D.P. ); [PERSON]SS] (W.J.) 2  
[PERSON]  
1 Department of Information Technology, Ghent University/IMEC, 9052 Ghent, Belgium;  
[PERSON]ESS] (D.P. ); [PERSON]SS] (W.J.) 2  
Footnote 1: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 2: [[https://www.mdpi.com/journals/pdf/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/111/11/111/11/111/11/111/111/111/11/111/111/111/11](https://www.mdpi.com/journals/pdf/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/111/11/111/11/111/11/111/111/111/11/111/111/111/11)]([https://www.mdpi.com/journals/pdf/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/111/11/111/11/111/11/111/111/111/11/111/111/111/11](https://www.mdpi.com/journals/pdf/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/11/111/11/111/11/111/11/111/111/111/11/111/111/111/11))  
discussed in [2], and the use of LoRa for I4.0 applications is discussed in [3]. In the 2.4 GHz industrial-scientific-medical (ISM) band, Bluetooth Low Energy (BLE), IEEE 802.15.4 (ZigBee, Thread, 6 LowPAN), and IEEE 802.11 (WiFi) are widely used. New wireless technologies such as software-defined networks (SDN) improve the overall system's efficiency and have shown to facilitate I4.0 applications [4]. With the existence of different technologies, the first choice to be made when designing a wireless network for IIoT is what technology will be used. This decision can be made on technological aspects, such as battery life, coverage, and throughput, but also on the technologies that are available on specific sensor modules that are needed. One example of the need for high-throughput communication in FoF is quality inspection via computer vision in an electric motor production hall [5]. Next to the high-throughput wireless local area network (WLAN), wireless sensor networks (WSN) with strict latency requirements are often used for process and robot control. Timing is also critical for the communication of automated guided vehicles with a backend server. Body area networks are a third category, as monitoring and protecting workers' health is another key challenge of FoF [6]. This can be obtained from radar-based monitoring systems or via information gathered by wearables. An example of the use of wearables in an industrial environment is posture tracking of factory operators, which not only allows for optimizing workbench configurations, but also identifying workload identification [7]. As different wireless technologies are used for different purposes, it is clear that the main challenge for network operators is the interoperability and coexistence of existing technologies as well as integration with state-of-the-art technologies, such as the software-defined radio (SDR). When the choice of which wireless technology to use is made, a network topology is selected and the location of access points (APs) is determined during the network-planning phase. Traditionally, network-planning and rollout is a one-time action during which the locations and configurations of APs are determined [8]. This assumes a static environment where a new planning action is performed whenever the environment changes. In FoF, requirements are dynamic, machinery is added or replaced, and the floor plan might be reorganized from time to time [9]. Therefore, maintenance is important after the network rollout, as an updated environment layout can cause coverage holes. Additionally, firmware and security updates may be required, and interference issues may arise when a wireless technology is added. An industrial environment is often characterized by the presence of large metallic objects [10].