The Industrial Internet of Things (IIoT) is considered a key enabler for Industry 4.0. Modern wireless industrial protocols such as the IEEE 802.15.4e Time-Slotted Channel Hopping (TSCH) deliver high reliability to fulfill the requirements in IIoT by following strict schedules computed in a Scheduling Function (SF) to avoid collisions and to provide determinism. The standard does not define how such schedules are built. The SF plays an essential role in 6TiSCH networks since it dictates when and where the nodes are communicating according to the application requirements, thus directly influencing the reliability of the network. Moreover, typical industrial environments consist of heavy machinery and complementary wireless communication systems that can create interference. Hence, we propose a distributed SF, namely the Channel Ranking Scheduling Function (CRSF), for IIoT networks supporting IPv6 over the IEEE 802.15.4e TSCH mode. CRSF computes the number of cells required for each node using a buffer-based bandwidth allocation mechanism with a Kalman filtering technique to avoid sudden allocation/deallocation of cells. CRSF also ranks channel quality using Exponential Weighted Moving Averages (EWMAs) based on the Received Signal Strength Indicator (RSSI), Background Noise (BN) level measurements, and the Packet Delivery Rate (PDR) metrics to select the best available channel to communicate. We compare the performance of CRSF with Orchestra and the Minimal Scheduling Function (MSF), in scenarios resembling industrial environmental characteristics. Performance is evaluated in terms of PDR, end-to-end latency, Radio Duty Cycle (RDC), and the elapsed time of first packet arrival. Results show that CRSF achieves high PDR and low RDC across all scenarios with periodic and burst traffic patterns at the cost of increased end-to-end latency. Moreover, CRSF delivers the first packet earlier than Orchestra and MSF in all scenarios. We conclude that CRSF is a viable option for IIoT networks with a large number of nodes and interference. The main contributions of our paper are threefold: (i) a bandwidth allocation mechanism that uses Kalman filtering techniques to effectively calculate the number of cells required for a given time, (ii) a channel ranking mechanism that combines metrics such as the PDR, RSSI, and BN to select channels with the best performance, and (iii) a new Key Performance Indicator (KPI) that measures the elapsed time from network formation until the first packet reception at the root.

中文翻译：

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密集工业6TiSCH网络的分布式信道排名调度功能

工业物联网（IIoT）被认为是工业4.0的关键推动力。遵循IEEE 802.15.4e时隙信道跳变（TSCH）之类的现代无线工业协议，可以通过遵循调度功能（SF）中计算的严格调度表来避免冲突并提供确定性，从而提供高可靠性以满足IIoT中的要求。该标准未定义如何构建此类时间表。SF在6TiSCH网络中起着至关重要的作用，因为它根据应用程序要求指示节点在何时何地进行通信，从而直接影响网络的可靠性。此外，典型的工业环境由重型机械和会产生干扰的互补无线通信系统组成。因此，我们提出了一个分布式SF，即通道等级调度功能（CRSF），用于在IEEE 802.15.4e TSCH模式下支持IPv6的IIoT网络。CRSF使用基于卡尔曼滤波技术的基于缓冲区的带宽分配机制来计算每个节点所需的信元数量，以避免信元的突然分配/解除分配。CRSF还基于接收信号强度指示器（RSSI），背景噪声（BN）级别测量和数据包传输速率（PDR）指标，使用指数加权移动平均值（EWMA）对信道质量进行排名，以选择最佳的可用通信信道。在类似工业环境特征的场景中，我们将CRSF与乐团和最小调度功能（MSF）的性能进行了比较。根据PDR，端到端延迟，无线电占空比（RDC），以及第一个数据包到达的经过时间。结果表明，CRSF在所有情况下均以周期性和突发流量模式实现高PDR和低RDC，但代价是增加了端到端延迟。此外，在所有情况下，CRSF都比Orchestra和MSF更早地提供第一个数据包。我们得出结论，对于具有大量节点和干扰的IIoT网络，CRSF是可行的选择。我们的论文的主要贡献是三方面的：（i）一种带宽分配机制，使用卡尔曼滤波技术有效地计算给定时间所需的小区数量；（ii）一种结合了诸如PDR，RSSI等指标的信道排名机制和BN来选择效果最佳的频道，