We present RoboTheater, a multi-robot storytelling platform, designed to explore and demonstrate the expressive capabilities of robots in stage execution. RoboTheater bridges computational narrative generation with embodied robotic execution, enabling robots to perform with varied dialogues and movements to create immersive stage narratives. The system uses large language models (LLMs) to generate structured scripts that are mapped into robots’ movements, speech, and visual projections, with all commands sent over a wireless network. A user study with 13 participants was conducted to evaluate the system’s usability and gather feedback. Our findings indicate that the RoboTheater effectively conveys emotion and character through multimodal cues, sustaining audience engagement and immersion. The work expands multi-robot storytelling and paves the way for creative, narrative applications.

6TiSCH is a protocol stack designed for industrial IoT applications, offering high reliability and ultra-low power consumption through Time-Slotted Channel Hopping (TSCH). A fundamental requirement of 6TiSCH is to ensure stable and efficient network synchronization, especially during the joining phase when many devices are attempting to connect. The standard provides a wide range of synchronization configurations to accommodate diverse deployment environments. However, it does not provide guidelines for network administrators on how to select appropriate configurations for different applications. In addition, existing models and approaches primarily focus on optimizing the initial synchronization phase, without discussing how synchronization is maintained afterward. This paper introduces a synchronization model for 6TiSCH networks to fill these gaps, enabling administrators to easily evaluate synchronization performance across different configurations and adapt the following five parameters to specific network conditions: Enhanced Beacon (EB) interval, Keep-Alive (KA) period, number of neighbors, link quality, and slotframe duration. By comparing the model’s predictions with detailed synchronization process simulations, we demonstrate that our model achieves 92.3% accuracy within a ±10-second margin when predicting synchronization time in low-to medium-density network scenarios. We conducted an exhaustive simulation campaign to evaluate the model’s performance in predicting synchronization time, packet count, and energy consumption, using 3,125 network settings with 100 runs per setting. Based on the analysis, we provide recommended settings for EB interval and KA period under different traffic loads, as indicated by slotframe durations. These recommendations ensure reliable synchronization during the joining phase across diverse network deployments and environmental conditions.

IEEE 802.15.4 is the core of multiple industrial standards such as WirelessHART, ISA100.11a, and 6TiSCH. It provides ultra-low-power operation and high reliability for battery-powered devices requiring a 5-10 year lifetime. However, due to its narrow frequency bandwidth, it is rarely used as a wireless ranging technique. Its low resolution in the time domain makes it difficult to precisely determine the arrival time of the signal, which is essential for Time-of-Flight ranging. Emerging approaches, such as WiFi fingerprinting, show promising localization performance by using learning methods to find the pattern mapping between signal characteristics and positions.This paper explores the potential of using learning approaches over IEEE 802.15.4 radios for ranging, based on RSSI and Round Trip Timing (RTT) samples. As a preprocessing step, groups of RTT samples are fed into a Gaussian Mixture Model (GMM), extracting two sets of features: the mean, variance, and weight of two distributions (line-of-sight and non-line-of-sight). Together with the mean and variance of the Received Signal Strength Indicator (RSSI) and RTT samples, 10 features are used as the input to a multilayer perceptron network to predict the distance between the requester and reflector.The approach has been evaluated using IEEE 802.15.4 devices in three different scenarios: an empty football field, an underground parking lot, and an office area. The results show that with dedicated models trained using datasets collected from each scenario, the ranging prediction errors of 0.25 meters, 0.42 meters, and 0.58 meters at 80% probability are achieved in these three scenarios, respectively. With a single model trained using a combined dataset from all three scenarios, prediction errors of 0.41 meters, 0.60 meters, and 0.97 meters at 80% probability are achieved.

6TiSCH is an internet engineering task force (IETF)-standardized protocol stack for industrial internet of things (IoT) applications. It employs time-slotted channel hopping (TSCH) in the MAC layer for robust reliability and ultra-low power consumption. By utilizing the RPL routing topology, the TSCH layer synchronizes devices across a network. However, in mobile scenarios, such as asset tracking, the RPL’s slow responsiveness delays device disconnection from the current network, hindering swift reconnection to a new network at a different location. To address this, a rapid mobility-aware method,RapDAD, is proposed in this article, functioning at the MAC layer. This method detects device cluster movement swiftly within a warehouse, bypassing reliance on RPL routing. The outcome demonstrates that a network comprising 100 6TiSCH devices can achieve disconnection within a mere 2 min upon root deactivation, simulating a transition from one location to another. This is a remarkable improvement compared to the original 10-h process of 6TiSCH network.

The single-chip micro-mote (SC$\mu \text{M}$) is a$2\times 3$mm2single-chip crystal-free mote-on-chip. SC$\mu \text{M}$implements the IEEE802.15.4 and BLE standards and can communicate with off-the-shelf radios compliant to those standards. SC$\mu \text{M}$exclusively uses on-chip oscillators, including a 2.4-GHz LC oscillator to synthesize the communication frequency, and a 2-MHz RC oscillator to clock the chip rate. The challenge is that the LC oscillator drifts at 2100 ppm over a temperature range of 45 °C, far from the 40-ppm maximum drift mandated by the IEEE802.15.4 standard. While one-shot calibration is possible, any temperature change causes IEEE802.15.4 communication to fail. This article describes a continuous calibration approach for SC$\mu \text{M}$to adapt the tuning of its oscillators as the temperature changes. Experimental results show that it allows SC$\mu \text{M}$to keep communicating with an IEEE802.15.4 radio even under the extreme condition of using a hair dryer to heat up the chip at 3 °C/min. Under these conditions, the drift of the LC oscillator stays within the ±40-ppm limit over 94% of the time. Similarly, the drift of the 2-MHz RC oscillator stays within ±1000 ppm limit 99.98% of the time.

The single-chip micro mote (SC$\mu \text{M}$) is a crystal-free single-chip mote that brings us one step closer to the Smart Dust vision, in particular, as it can communicate with off-the-shelf IEEE802.15.4 and Bluetooth low energy devices. However, before it can be part of such networks, the crystal-free SC$\mu \text{M}$chip needs to be able to accurately tune its communication frequency to synchronize to the network. This is a challenge since its onboard RC and LC-based resonating circuits have a drift rate that can be three orders of magnitude worse than crystal-based oscillators typically used in today’s radios. This article introduces QuickCal, a solution that allows an SC$\mu \text{M}$chip to self-calibrate against off-the-shelf devices dedicated to assisting with its calibration. We show that an SC$\mu \text{M}$chip can self-calibrate against this QuickCal Box in fewer than 3 min. We further validate that once it has self-calibrated, an SC$\mu \text{M}$chip can reliably communicate with off-the-shelf IEEE802.15.4 devices. Finally, we demonstrate a heterogeneous network—composed of an SC$\mu \text{M}$chip and an OpenMote device—implementing a full 6TiSCH Industrial IoT protocol stack, which uses time synchronization and channel hopping. This is the first time that a crystal-free radio is participating in a channel-hopping-enabled TSCH network.

The convergence of operational and information technologies in the industry requires a new generation of IP-compliant communication protocols that can meet the industrial performance requirements while facilitating the integration with novel web-based supervisory control and data acquisition (SCADA) systems. For more than a decade, the industry has relied on time-slotted channel hopping (TSCH) communication technology to meet these performance requirements through standards such as WirelessHART and ISA100.11a. TSCH-based networks have proven to yield over 99.999% end-to-end reliability, supporting flow isolation and QoS management while ensuring over a decade of battery lifetime. However, these technologies were designed to address the factory use cases of a decade ago, not considering IP compliance or standardized network management and resource orchestration as a must. The Internet Engineering Task Force (IETF) and the 6TiSCH working group (WG) have been actively working on this challenge by designing protocols to bridge the performance of industrial solutions with IP-compliant networks. The effort has resulted in 6TiSCH, a set of specifications that define the IPv6 control plane to manage and orchestrate a TSCH network. 6TiSCH provides the missing elements for zero-configuration TSCH network bootstrap, efficient network access authentication, and distributed and modular scheduling mechanisms. As a cross-layer effort, 6TiSCH leverages and integrates other IETF specifications and the WG has also driven the definition of novel specifications in other IETF WGs. An ultimate goal of this effort is the definition of a fully functional architecture where a combination of IETF protocols enables the envisioned convergence on top of the IEEE industrial standard. This paper introduces the work done by the 6TiSCH WG at IETF, evaluates the performance of the reference implementation, and discusses the 6TiSCH software ecosystem.

The 6TiSCH working group is standardizing the low-power wireless protocol stack for the Industrial IoT. The default scheduling function (SF0) standardized by 6TiSCH uses simple random slot selection. This paper proposes the Low Latency Scheduling Function (LLSF), a new scheduling function which daisy-chains timeslots rather than picking them randomly. We implement LLSF in OpenWSN and evaluate its performance experimentally. LLSF yields 82.8% lower end-to-end latency ona 5-hop path than SF0, at no extra costs.

The Industrial Internet of Things (IIoT) vision relies on reliable low-power wireless technologies and a complete standardized protocol stack that brings Internet connectivity to constrained end devices. Currently IEEE802.15.4-2015 TSCH provides reliability over low-power wireless technologies and the IETF has defined a protocol stack that is suitable to constrained devices. Open-source initiatives contributing to the development of network stacks for embedded devices, and the availability of open hardware platforms that facilitate prototyping IIoT applications contributes to the adoption of IIoT technologies. To realize the IIoT vision, this demo presents the Open- WSN and OpenMote projects, which provide both an open-source software implementation of the IEEE low-power wireless technologies and the IETF protocol stack, and an open-source hardware platform that meets the requirements to prototype IIoT applications.