# Time Management in Wireless Sensor Networks for Industrial Process Control
## 5 Conclusions  
This article has presented a complete, low-cost, and highly effective time management solution for wireless sensor networks (WSNs) deployed in industrial process control applications. Using COTS hardware and an implementation based on the IEEE 802.15.4-2020 standard operating in TSCH mode, the proposed approach has demonstrated that wireless control can indeed meet the strict timing constraints previously reserved for wired systems.  
The core contribution lies in the design and validation of a lightweight time synchronization algorithm that utilizes structured timeslot grouping and enhanced beacon-based coordination to achieve sub-millisecond drift between wireless nodes. Through the careful division of communication tasks, strict adherence to timing templates, and precise scheduling within a 6000-timeslot slot frame, the system enables a reliable real-time data exchange in environments where timing predictability is crucial. Validation experiments, conducted using a logic analyzer and a testbed built on STM32 microcontrollers and AT86 RF212B transceivers, confirmed consistent synchronization accuracy below 600 microseconds even after prolonged operation, demonstrating system robustness.  
In addition to the timing algorithm itself, this paper introduces a modular software architecture built around a custom hardware abstraction layer (HAL) and a CMSIS-compliant transceiver driver. This framework not only improves the timing consistency and execution predictability, but also supports portability across multiple STM32 microcontroller families and even on those from other manufacturers, allowing developers to reuse core logic without rewriting low-level code. Such modularity opens the door to future enhancements,including porting the implementation to higher-performance platforms or integrating the solution into more complex industrial systems.  
While the results are promising for simple star topologies, there remains significant potential for extension. Custom hardware with high-precision oscillators could improve synchronization and enable even shorter slot frames, enhancing responsiveness and efficiency. Future work will explore the following: (a) hierarchical synchronization structures or integration into mesh topologies to support larger-scale industrial WSNs; (b) validation in noisy industrial environments by using channel hopping to reduce possible interference from outside sources; and (c) node redundancy to increase the robustness of the wireless network in general and the control loops in particular.  
Ultimately, this work contributes a reproducible and scalable foundation for transitioning from wireless monitoring to wireless control in industrial automation. By showing that time-sensitive feedback loops can be reliably closed over wireless links, it challenges the traditional reluctance toward wireless adoption in control loops and paves the way for more flexible and maintainable industrial communication architectures.  
Conceptualization, A.R. and P.D.; methodology, A.R. and P.D.; software, A.R., M.H., and R.M.; validation, A.R., P.D., M.H., and R.M.; formal analysis, P.D.; investigation, A.R., P.D., M.H., and R.M.; resources, A.R. and M.H.; data curation, A.R. and P.D.; writing--original draft preparation, A.R.; writing--review and editing, A.R., M.H., and R.M.; visualization, A.R. and P.D.; supervision, P.D.; project administration, P.D. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Data Availability Statement: Data is contained within this article.  
The authors declare no conflicts of interest.