In Wireless Networked Control Systems (WNCSs), the feedback control loops are closed over a wireless communication network. The proliferation of WNCSs requires efficient network resource management mechanisms since the control performance is significantly affected by the impairments caused by network limitations. In conventional communication networks, the amount of transmitted data is one of the key performance indicators. In contrast, in WNCSs, the efficiency of the network is measured by its ability to facilitate control applications, and the data transmission rate should be limited to avoid network congestion. In this work, we consider an experimental setup where multiple control loops share a wireless communication network. Our testbed comprises up to five control loops that include Zolertia Re-Mote devices implementing IEEE 802.15.4 standard. We propose a novel relevance- and network-aware transport layer (TL) scheme for WNCSs. The proposed scheme admits the most important measurements for the control process into the network while taking current network conditions into account. Moreover, we propose a mechanism for the scheme parameters adaptation in dynamic scenarios with unknown network statistics. Unlike the conventional TL mechanisms failing to provide adequate control performance due to either congestion in the network or inefficient utilization of available resources, our method prevents network congestion while keeping the control performance high. We argue that relevance- and network-awareness are critical components of network protocol design to avoid control performance degradation in practice.

翻译：在无线网络控制系统（WNCSs）中，反馈控制回路通过无线通信网络闭合。由于控制性能显著受网络限制造成的损耗影响，WNCSs的普及需要高效的网络资源管理机制。在传统通信网络中，传输数据量是关键性能指标之一；而在WNCSs中，网络效率以其支持控制应用的能力来衡量，且数据传输速率应受限制以避免网络拥塞。本研究考虑多个控制回路共享一个无线通信网络的实验场景。我们的测试平台包含多达五个控制回路，这些回路采用实现IEEE 802.15.4标准的Zolertia Re-Mote设备。我们针对WNCSs提出了一种新颖的、具备相关性与网络感知能力的传输层（TL）方案。该方案在考虑当前网络状况的同时，允许对控制过程最重要的测量数据接入网络。此外，我们提出了一种机制，用于在网络统计特性未知的动态场景中自适应调整方案参数。与因网络拥塞或资源利用效率低下而无法提供充分控制性能的传统TL机制不同，我们的方法在保持高控制性能的同时防止了网络拥塞。我们认为，相关性与网络感知能力是网络协议设计中的关键要素，可避免实际应用中控制性能的退化。