This paper presents contributions to coding short packets that can be applied to wireless links in the Industrial Internet of Things, Cyber-Physical Systems, and Digital Twin Systems. The problem of efficiency and simplicity in coding schemes for short messages remains a research challenge. Sparse Vector Codes, based on Compressive Sensing techniques, offer good performance with a reasonable margin of simplification of the algorithms involved. In this paper, several SVC configurations are proposed and performance results are presented with comparisons to other channel coding schemes. A first study of the achievable range of these networks is also provided and their performance is compared to existing technologies. The results confirm the potential of SVC in industrial wireless systems.

The envisaged fifth-generation (5G) and beyond networks offer unprecedented breakthroughs in media service delivery, stringent requirements, and challenging use cases. In such context, point-to-multipoint communications have proved to be highly efficient in delivering high-quality multimedia services over wireless networks. For the upcoming Beyond-5G (B5G) system releases, the Multicast/Broadcast Services (MBS) capability is an appealing feature that addresses the ever-growing traffic demands, disruptive multimedia services, massive connectivity, and low-latency applications. This paper addresses the multicast users’ channel quality diversity throughout multi-rate multicasting aided non-orthogonal multiple access (NOMA) over B5G MBS use cases. We propose a tailored radio resource management (RRM) strategy aided by K-Means subgrouping to deal with such diversity. We characterize and identify conditions for an effective coexistence of the benchmarks conventional multicast scheme (CMS) and subgrouping based on OMA (SOM) with the proposed subgrouping based on NOMA (SNOM). The proposed solution is assessed under a wide range of users’ distributions, throughput requirements, and network conditions of an MBS use case recreated through link-level millimeter-wave (mmWave) simulations.

The stringent requirements of the latest immersive applications (i.e., 360° video, VR, AR, XR, etc.) combined with the scarcity of radio resources are challenging the service operators of the various telecommunication networks. In the recent literature, HetNets have been proposed as an alternative to overcoming these challenges. In previous work, the authors presented SVORA, an architecture for integrating different radio technologies, combining virtualized/open RAN architectures and SBA-based RAN for efficient spectrum usage. In this work, the authors upgrade the previously proposed solution to deliver immersive video efficiently. The paper presents imeNF, a new set of Network Functions that support delivering high-bitrate immersive video-based applications with increased quality of service. Simulations-based testing shows how, based on imeNF, a 16k video can be sent with delays of 15 ms, while traditional D-RAN, V-RAN, and O-RAN-based approaches take more than 300 ms.

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.

Derived from the work at IMT-2020, the standard DECT2020-NR provides non-cellular communication solutions for applications requiring strict latency and reliability for flexible and adaptive deployments. Examples include industrial and audiovisual communications. This work-in-progress analyzes the physical layer performance of DECT2020-NR in an industrial environment. Different types of communication links are considered and various propagation channel conditions and system configurations are simulated. The results obtained confirm the need for a MAC access layer with link control techniques to ensure the reliability requirements of industrial applications.

Industry 4.0 aspires to digitize factories processes wholly. Wireless technologies represent one of the elements of this goal. However, the current standards and proprietary solutions need to meet the industry’s tight requirements for various use cases, such as smart warehouses, where robots manage and control entire tasks. One of the key research challenges toward replacing wired fieldbuses with wireless links is the design of wireless systems that address short packet transmissions and multi-user environments. Nevertheless, this challenge is partially obstructed by the limits of the current proposals and the industrial channel models. The authors detect as a potential solution the optimization of IEEE 802.11ax that, due to the use of OFDMA, could offer a high-performant system for smart warehouses. This article proposes an ad-hoc wireless system based on IEEE 802.11ax for smart warehouses that comprises optimization for MAC and PHY layers. Furthermore, two retransmission schemes based on frequency domain are described. This article proposes a methodology to evaluate the latency and reliability performance. Compared to previous proposals, the system shows improved performance.

This paper describes the design of a Broadcast Core Network (BCN). The BCN is intended to enable the integration of existing terrestrial broadcast systems into a 5G/6G ecosystem. The existing multimedia content distribution architecture in current broadcast networks and the capabilities of 5G access and core networks (5GC) are analyzed to dissect their limitations. We show, inter alia, how the lack of an equivalent data plane makes it impossible to import a 5GC as a solution. We propose a dynamic model that addresses the necessary structure for integrating a BCN in today’s broadcast networks. The paper then considers the evolution of the BCN up to its integration into a 5G/6G cellular network ecosystem. The required architectural components are described. Detailed definitions of the microservices are included, along with the relationships and message calls to enable relevant use cases. Finally, a simulation and lab prototype were developed to validate the proposal. The lab platform is based on multimedia content broadcasting nodes using ATSC 3.0 and a BCN prototype for its control. The results demonstrate the ability of the proposed solution to maximize spectrum utilization and improve the efficiency of current systems.

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

Upgrading wired industrial field buses with wireless counterparts is a key driver for future industrial applications and systems. This migration faces significant challenges associated with security, reliability, and lack of generally accepted standards. Moreover, wireless PHY and MAC layer developments require accurate, reliable, and realistic propagation channel models. Reliable models for Delay Profile and Doppler Spectra are scarce in the literature. This work analyses channel models based on reliable empirical data. It includes a description of the source databases, the processing methods, and the first results of multipath distribution and Doppler metrics. The results indicate that previous assumptions on Laplacian Doppler should not be taken for granted in industrial environments.

The Internet of Things (IoT) plays a critical role in enabling the seamless integration of disparate devices. Future IoT will rapidly expand its coverage to offer future worldwide omnipresent applications and services by merging communications in diverse spatial domains to build the space–air–ground–ocean-integrated network (SAGOI-Net). SAGOI-Net will include a significant number of battery-powered network nodes, such as satellites, unmanned vehicles, and underwater devices, due to the extremely vast geographic reach and dynamics in free space. Given the battery limitations, high-energy-efficiency communications and networking will be critical to the future system. Green SAGOI-Net seeks to not only bring ubiquitous connectivity to every corner of the globe but also to deliver more data with the same amount of energy.

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.

Wireless backhaul has recently gained a significant amount of interest as a cost-effective solution in comparison with conventional backhaul technologies with dedicated microwave links or fiber optics. Self-interference cancellation (SIC) is an enabling technology that allows wireless backhaul to operate in the more spectrum-efficient in-band full-duplex (IBFD) operation mode instead of the out-of-band mode. Compared to Wi-Fi IBFD transceivers, wireless in-band backhaul systems face some unique challenges, such as significantly higher transmission power and much larger propagation delay spread for the self-interference signal, especially in the low-frequency bands under 1 GHz, which often prevent accurate SIC performance. The SIC is often implemented with an interference-cancelling filter, where the filter weights are essentially the channel estimates of the self-interference signals. In this paper, a frequency-domain Radio Frequency (RF) SIC (RF-SIC) framework with a novel filter weight optimization algorithm is proposed to tackle the challenges of wireless in-band backhaul. The proposed RF-SIC does not require a dedicated training phase which needs to stop the transmission of the backhaul signal. Moreover, it has the capability of tracking the self-interference channel variation since the filter weights are updated in a block-by-block fashion.

Industry 4.0 is expected to change radically the current ecosystem of industrial technologies, including commu-nication systems. Novel industrial scenarios will request to fulfill tight requirements, such as low latency and ultra-high reliability. Classical wired solutions lack scalability and mobility and assume high deployment costs. However, in wireless communications, the propagation channel appears as an additional challenge to overcome the limitations of wired systems. This paper addresses several requirements simultaneously using Non-Orthogonal Mul-tiple Access (NOMA). An efficient superframe structure has been designed to deliver additional services (i.e., high-quality video service) and transmit specific services (i.e., critical services). Furthermore, the performance of the additional service (i.e., best effort) has been tested in terms of availability and capacity. Then, another Key Performance Indicator (KPI) deeply analyzed in this paper is energy consumption. Finally, the entire communication system has been evaluated from different perspectives, and some guidelines have been provided to detail the best configurations depending on the optimization KPI.

This paper presents a method to evaluate the feasibility of using wireless links as part of functional safety systems. We present an analytical model to describe the wireless safety links' performance operating in fading industrial environments. The work considers integrity failures, wrong addressing, message sequence errors, and masquerade events. The contributions of each perturbation to the overall system residual error are modeled with equations. Moreover, a MAC scheme based on the tools suggested in IEC 61784–3 is proposed and validated under industry-recommended use case parameters. The results show that the variation of the frame structure and application-specific parameters impact the overall residual error. The work concludes that the residual error probability of the CRC dominates residual error performance, but it may be reduced using consistent countermeasures against other possible sources of error.

This paper presents a methodology to characterize the impact of deep fading in wireless links related to safety functions for industrial applications. We analyze the different methods available to describe the residual error probability and discuss their application to practical wireless systems, where fading is a key propagation impairment. An analytical method to derive the residual error probability in fading channels is proposed, and calculated curves are compared to empirical results obtained by system simulations. The procedure is illustrated using two well known CRC polynomials with codeword lengths and appropriate safety data rates for industry cases. The system residual error probabilities are compared with those associated to SIL targets. Moreover, an erroneous packet filtering technique is proposed to approach IEC 61508 specifications. Results show that the choice of a proper CRC is critical in safety wireless and demonstrate that CRCs, combined with filtering techniques, can achieve performance values in the range of SIL targets.

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.

The Industry 4.0 concept is the result of latest technical advances that have completely changed the existing industrial vision, not only from the mechanical point of view, but also from the Machine-to-Machine (M2M) communication perspective. This revolution encompasses wireless communication technologies that are expected to be the replacement for traditional wired and fixed communication systems. However, industrial propagation channels are still a challenge for wireless industrial network deployments. This paper addresses this problem by proposing spatial diversity based retransmissions. Two general retransmission schemes have been tested: default and smart. Moreover, specific time scheduling choices have been proposed. The impact of the number of transmitters in relation to communication reliability has been analyzed. Results show that the use of spatial diversity based retransmissions makes restrictive reliability values feasible under realistic conditions. In fact, in the case of smart retransmissions, adding a second transmitter the reliability increases around 8 dB. Moreover, whereas the channel coherence time is a critical parameter for time based retransmissions, in the case of spatial diversity, the reliability performance has no dependency on the channel coherence time.

The burgeoning capabilities of Web browsers to exploit full-featured devices can turn the huge pool of social connected users into a powerful network of processing assets. HTML5 and JavaScript stacks support the deployment of social client-side processing infrastructure, while WebGL and WebCL fill the gap to gain full GPU and multi-CPU performance. Mobile Grid and Mobile Cloud Computing solutions leverage smart devices to relieve the processing tasks to be performed by the service infrastructure. Motivated to gain cost-efficiency, a social network service provider can outsource the video analysis to elements of a mobile grid as an infrastructure to complement an elastic cloud service. As long as users access to videos, batch image analysis tasks are dispatched from the server, executed in the background of the client-side hardware, and finally, results are consolidated by the server. This paper presents SaW (Social at Work) to provide a pure Web-based solution as a mobile grid to complement a cloud media service for image analysis on videos.

Scattering signals on wind turbines may lead to degradation problems on the communication systems provided in the UHF band, such as terrestrial television broadcasting, broadband wireless systems or public safety services. To date, despite the continuous requests from the International Telecommunication Union for studies on this field, no channel model has been developed to characterize signal propagation under these particular conditions. In response to this necessity, this paper presents a complete Tapped Delay Line (TDL) channel model to characterize multipath propagation in presence of a wind farm, including novel scattering modeling and Doppler spectra characterization. As proved later, this channel model, which is based on both theoretical development and empirical data obtained in the surroundings of a real wind farm, is adaptable to the particular features of any case under study: wind turbine dimensions, working frequency, and relative location of the wind farm, transmitter and receivers.