Emerging applications in the wireless domain such as factory automation or extended reality require high reliable and deterministic communications. New scheduling mechanisms introduced in current state-of-the-art Wi-Fi (i.e. 802.11ax, 802.11be) offer better performance, but in many cases not sufficient to meet the requirements of the aforementioned applications. In this paper, we present a hardware implementation of Scheduled Time-Sensitive Transmission Opportunity (S-TXOP) over Wi-Fi, S-TXOP provides accurate time synchronization and time-aware scheduling to enable highly efficient deterministic wireless communications. We describe a field-programmable gate array software-defined radio S-TXOP implementation, and show numerical and experimental results supporting low cycle time transmissions with determinism.

This paper presents a methodology to evaluate the safety performance in wideband wireless systems through frequency-selective channels. We propose a methodology based on the error distribution along an Orthognal Frequency Division Multiplexing (OFDM) symbol for a given channel situation. From there, a mathematical method that considers the benefits of channel coding is derived to characterize the performance of safety communication layer tools as defined by the regulatory framework. This process is illustrated using an example with industry-specific data. It is shown that the effect of fading variability benefits the safety performance of the wireless system. The analytical model shows that variability reduces the probability of events with many errored subcarriers. This reduction facilitates the identification of a higher number of situations that put the safety function at risk. The possibilities of reaching some SIL limits within the proposed scenario are also explored.

Presents corrections to the paper, On the Feasibility of Wireless Communications for Safety Applications in Industry.

To achieve high reliability for Wi-Fi, we propose to use network coding (NC) as a proactive inter-frame (packet-level) redundancy technique at the medium access control (MAC) layer, which has the advantage of low latency and high spectral efficiency compared to the existing retransmission and repetition techniques. In this paper, we explore practical ways to integrate NC in Wi-Fi systems and conduct over-the-air experiments in an office environment using a Wi-Fi-based platform, where NC is implemented as a software layer. The experiment results show that NC can achieve up to two orders of magnitude reliability gain over the baseline repetition scheme with the same spectral efficiency. When interferences exist in Wi-Fi transmissions, but the packet erasures are sufficiently uncorrelated, using NC can achieve very high reliability. When the correlation increases the performance gain of NC degrades, but it still maintains a significant advantage over repetition.

SiliconBurmuin is aimed at creating a multi-disciplinary neurocomputing community in the Basque Country, bringing together technology and scientific research centres and industry companies. This community will: (1) identify key biological structures and mechanisms that play a major role in vision across species, and (2) transform this knowledge into novel mathematical formalisms, neuromorphic designs and algorithms to solve industry challenges and enable new experiments of interest in neuroscience and clinical research. To achieve the latter objective in a time-effective manner, SiliconBurmuin will draw strong connections with the ongoing Horizon Europe NimbleAI project, with which it shares coordination. This is expected to allow reinforcement of ideas, knowledge and technology via a common prototyping platform where to implement IP from both projects. In addition to describing the research objectives and direction of SiliconBurmuin, this paper posits that co-coordination and co-funding of aligned projects at EU and regional levels might well be a catalyst for raising regional self-awareness of own potential and develop it to help fulfill global challenges, such as semiconductor sovereignty.

This article presents a methodology to characterize the reliability and safety capabilities of redundant wireless systems planned for an industrial application. The equations that describe the residual error are presented and studied in situations that model an industrial wireless scenario. We propose different voting systems and their performance is evaluated analytically and by simulations. Likewise, a voting system based on a combination of filtering and cross-checking techniques is proposed. This solution significantly reduces the probability of undetected dangerous events while maintaining availability under control. Moreover, an improved version with triple redundancy is also presented. The results demonstrate that it is possible to fulfill the requirements of standard IEC 61508 without compromising system availability statistics. The solutions have been implemented on hardware wireless prototypes to illustrate the effectiveness of the proposed voting systems.

This work discusses Access Point Coordination techniques for future 802.11 communications in the context of industrial Wireless TSN scenarios. A Coordinated OFDMA setup is proposed with a frame exchange scheme based on implicit wireless channel sounding prior to transmission. The scheduler assigns resource units to the users, trying to maximize the probability of all the STAs in the network to successfully deliver their data. In order to evaluate the quality of the channels without introducing overhead in the network, we propose a virtual sounding mechanism. We present simulation results first to validate the virtual sounding mechanism and, second, to show the achievable reliability of a Multi-AP network for a set of representative scenarios. These results highlight that Multi-AP can be effectively used to enhance the reliability of the network though special attention must be taken for time-varying scenarios.

Standard wireless systems are rapidly evolving to support the strict requirements of industrial applications. In this research line, wireless time-sensitive networking (TSN) is gaining momentum, thanks to the interest of wired TSN among the industries. A critical aspect of the wireless TSN research is the integration of wired and wireless TSN to create large-scale hybrid TSN networks. This integration is currently being discussed for 5G, whereas the integration between wired TSN and IEEE 802.11 is a step behind. To address this gap in the state of the art, this article discusses the integration challenges of wired TSN and wireless local area network technologies and proposes a hybrid TSN device architecture. Based on the architecture, we have developed a hybrid TSN network proof-of-concept. The proof-of-concept demonstrates that the hybrid TSN architecture can maintain the essential TSN services, including providing guaranteed latency in the 100-microsecond level.

Industrial control systems present numerous challenges from the communication systems perspective: clock synchronization, deterministic behavior, low latency, high reliability, flexibility, and scalability. These challenges are mostly solved with standard technologies over Ethernet, e.g., time-sensitive networking (TSN). As a research trend, it is expected that TSN will converge with wireless, leading to the Wireless TSN paradigm. Also, Wireless TSN is expected to be integrated with Ethernet TSN to create large-scale wired–wireless (Hybrid) TSN networks. The first step toward Hybrid TSN is the distribution of the clock reference from the wired to the wireless domain. In this article, we leverage existing Ethernet TSN and wireless technologies implementations (Wi-Fi and w-SHARP) and present two hardware architectures specifically engineered to enable the clock synchronization distribution among the network domains. The hardware architectures have been implemented over a system-on-chip field-programmable gate array platform. We demonstrate through several experiments that the implementation is able to fulfill the synchronization performance required by TSN.

With the uprising of new fields such as robotics, IoT or Augmented Reality, one of the main objectives of industrial modernization is the incorporation of safe and secure wireless technologies in the factory floor. However, nowadays wireless protocols can not fulfill the communication requirements of industrial networks, among which reliability and bound guaranteed latency are probably the most stringent ones. The lack of guaranteed low latency and ultra-high reliability of wireless networks are mainly derived from the error-prone nature of wireless propagation. Multi-link techniques are expected to provide enhanced reliability, latency and also protection against external interference. In this work, we assess the reliability and latency enhancement of the Multi-Link technique proposed in 802.11be. The assessment is done through simulation means using realistic industrial propagation and interference models. The results shown in this paper prove that Multi-Link provides an enhancement in wireless reliability and latency.

This paper discusses an implementation of a wireless-wired TSN network, named SHARP, which delivers hard real-time capabilities with bounded latencies of hundreds of microseconds and clock synchronization with tens of nanosecond accuracy along both wired and wireless segments. It has been demonstrated that the network is able to maintain the most important TSN services in various situations of critical real-time and non-critical traffic in the context of a representative Industry 4.0 application. The communication solution presented here is expected to pave the way for massive digitization of future flexible smart factories, especially when combined with other technologies to be commercially available in the short-medium term like 5G.

Real-time Industrial applications in the scope of Industry 4.0. present significant challenges from the communication perspective: low latency, ultra-reliability, and determinism. Given that wireless networks provide a significant cost reduction, lower deployment time, and free movement of the wireless nodes, wireless solutions have attracted the industry attention. However, industrial networks are mostly built by wired means because state-of-the-art wireless networks cannot cope with the industrial applications requirements. In this article, we present the hardware implementation of wireless SHARP (w-SHARP), a promising wireless technology for real-time industrial applications. w-SHARP follows the principles of time-sensitive networking and provides time synchronization, time-aware scheduling with bounded latency and high reliability. The implementation has been carried out on a field-programmable gate array-based software-defined radio platform. We demonstrate, through a hardware testbed, that w-SHARP is able to provide ultra-low control cycles, low latency, and high reliability. This implementation may open new perspectives in the implementation of high-performance industrial wireless networks, as both PHY and MAC layers are now subject to be optimized for specific industrial applications.

Critical communication requirements included in Factory Automation applications are complex to implement due to the difficulties encountered in guaranteeing high reliability and ultra-low latencies at the same time. In this work-in-progress, a technical solution for the physical layer is proposed: the Quasi-Cyclic LDPC of the Progressive Edge Growth family (QC-PEGLDPC). This coding scheme is considered as a promising candidate due to two main factors: the good decoding performance for short packet transmissions and the low latency that can be obtained by using full parallel decoding architectures. The obtained results are compared with the 5G New Radio coding scheme, which includes LDPCs as part of the solution for Ultra Reliable Low Latency (URLLC) use cases. In these first results, QC-PEG-LDPC shows a performance improvement of 1 dB when compared with the 5G LDPC codes for a message length of 128 bits. Latency analysis indicate that QC-PEG-LDPC could allow decoding latencies of 0.13 μs providing that the full parallel decoding architecture is enabled.

Wireless communications have attracted great interest from the industry due to its lower cost and the possibility of enabling new use cases. The new use cases are commonly related to mobile robotics, such as Unmanned Aerial Vehicles. The design of wireless systems for these use cases requires deep knowledge of the channel behavior. However, the weight and size of full channel sounders exceed the payload of most mobile robots. In addition, full channel sounders usually require wired time synchronization. Hence, channel measurements in these scenarios are constrained to use limited channel sounders, which can only measure some specific parameters (frame error rate, channel attenuation, etc.). In this paper, we present the design and implementation of a portable 802.11-based channel sounder combined with a sub-nanosecond wireless time synchronization algorithm. Thanks to the wireless time synchronization, the channel sounder can be used to periodically take complex baseband Channel Impulse Response samples synchronized to absolute time. From these samples, relevant channel parameters can be extracted, including the Power Delay Profile, Doppler spectrum, and channel delay. The verification of the channel sounder through a wireless channel emulator confirms its feasibility for mobile robotics applications.

The time-sensitive network paradigm envisions the integration of operation technology and information technology in the same network. One of the requirements for building time-sensitive networks is sharing a global time along the network. This requirement is especially critical in wireless systems, where there are few robust methods to perform accurate time transfer. In this article, the problem of time transfer over realistic wireless channels is studied, and a time distribution scheme is proposed. The time distribution scheme has three components: Precision time protocol, a novel timestamping method (enhanced timestamps) and an algorithm to implement the enhanced timestamps. The performance of the proposed scheme has been evaluated in MATLAB using the IEEE 802.11n Standard under several standard wireless local area network channel models. The results show that the system can reach subnanosecond time transfer accuracy under non-line-of-sight and time-variant conditions, but its performance greatly depends on the signal-to-noise ratio and on the channel variation rate.

Wireless communication technologies play an important role in today's society and, for that reason, wireless systems are almost ubiquitous. The keys of the success of wireless communications are, among others: reduced cost of wiring, implementation and maintenance or greater flexibility. Given these advantages, there is a growing interest in expanding the wired networks used in the most critical industrial applications to a wireless domain, fulfilling the real-time requirements of these applications. In addition, the incorporation of mobile devices to hybrid networks allows to expand the application area and obtain even more benefits from using wireless solutions. Nevertheless, guaranteeing the robustness and determinism required by factory automation applications where several Access Points (AP) are necessary to cover the entire wireless area is not an easy task. Therefore, in this paper, a novel soft-handover algorithm is presented. This algorithm guarantees an uninterrupted communication during the handover process required by the wireless devices together with a dynamic management of the resources within the hybrid (wired/wireless) scheme. To make this possible, the handover algorithm is combined with a slotted Medium Access Control (MAC) based on a superframe structure with a contention-free phase and a contention phase, where the contention-free phase is divided into uplink and downlink slots. The performance of the algorithm has been evaluated through OMNeT++ simulations.