Parallel Sequence Spread Spectrum based Ultra-Reliable Low Latency Communication for Factory Automation

Wireless technologies gain importance in various fields of industrial communication as they facilitate control and data acquisition tasks. In this context, Parallel Sequence Spread Spectrum (PSSS) is a promising new approach. The parametrization of a PSSS system is very flexible and thus can be precisely adapted to the application's requirements. Independent of the PSSS parametrization, the transmission resources can be assigned efficiently since their management is very flexible. With full duplex and a resource stream in both up- and downlink, even a network with high node density and varying QoS requirements can be served in a single PSSS system. Especially cycle times smaller than 1 ms are possible. A PSSS system for ultra low latency and highly reliable industrial applications is parametrized in the German research project ParSec. In ParSec, the PSSS system is evaluated analytically as well as in practice. In order to allow early measurements, in ParSec a rapid prototype system was developed, with which first PSSS measurements were performed. This paper gives an overview of the fundamental PSSS concept, while it points out the overall system's potential in industrial communication. Moreover, the measurement results are discussed to evaluate the bit error distribution in a PSSS frame. Rolf Kraemer IHP Microelectronics Frankfurt (Oder), Germany.

While current reliable and ultra low latency industrial communication is based on wired fieldbus systems, wireless communication is the key to enable future industrial applications. However, the reliability of state-of-the-art wireless technologies is not sufficient for many industrial application scenarios. Thus, novel wireless approaches are being investigated at the moment, from which three promising physical layer (PHY) technologies are depicted for detailed evaluation in this paper: Ultra Wide Band (UWB), Frequency Hopping Spread Spectrum (FHSS) and Parallel Sequence Spread Spectrum (PSSS). In order to assess each system’s performance, Key Performance Indicators (KPI) are derived from industrial application constraints. In this paper, industrial applications are therefore categorized by vital requirements such as spatial extent, number of nodes, cycle time, PER and user data length. The depicted technologies are evaluated regarding the KPIs error rate and coverage range in AWGN and industrial fading channel conditions.

In future 5G systems, the millimeter wave (mmWave) band will be used to support a large capacity for current mobile broadband. Therefore, the radio access technology (RAT) should be made available for 5G devices to help in distinct situations, for example device-to-device communications (D2D) and multi-hops. This paper presents ultra-wideband channel measurements for millimeter wave bands at 19, 28, and 38 GHz. We used an ultra-wideband channel sounder (1 GHz bandwidth) in an indoor to outdoor (I2O) environment for non-line-of-sight (NLOS) scenarios. In an NLOS environment, there is no direct path (line of sight), and all of the contributed paths are received from different physical objects by refection propagation phenomena. Hence, in this work, a directional horn antenna (high gain) was used at the transmitter, while an omnidirectional antenna was used at the receiver to collect the radio signals from all directions. The path loss and temporal dispersion were examined based on the acquired measurement data—the 5G propagation characteristics. Two different path loss models were used, namely close-in (CI) free space reference distance and alpha-beta-gamma (ABG) models. The time dispersion parameters were provided based on a mean excess delay, a root mean square (RMS) delay spread, and a maximum excess delay. The path loss exponent for this NLOS specific environment was found to be low for all of the proposed frequencies, and the RMS delay spread values were less than 30 ns for all of the measured frequencies, and the average RMS delay spread values were 19.2, 19.3, and 20.3 ns for 19, 28, and 38 GHz frequencies, respectively. Moreover, the mean excess delay values were found also at 26.1, 25.8, and 27.3 ns for 19, 28, and 38 GHz frequencies, respectively. The propagation signal through the NLOS channel at 19, 28, and 38 GHz was strong with a low delay; it is concluded that these bands are reliable for 5G systems in short-range applications.

Based on outdoor-indoor measurements we study the channel characteristics of wideband multiple-input-multiple-output (MIMO) wireless access with near-ground base-stations (BS). These provide broadband service to indoor nomadic users in suburban residential environments. We compare near-ground channel characteristics with those of a lamp-post BS for line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. Essentially path-loss models, spectral efficiencies for 2×2 and 4×4 MIMO systems, delay spreads and coherence bandwidth are evaluated. We found that in general lowering the BS array has a detrimental effect on path-loss and efficiencies. Up to 50% less efficiency was observed in the NLOS channel, and path-losses are moderately greater for both LOS and NLOS conditions. Our investigation also shows differences in the power delays profiles when varying the array height.

In Intelligent Transportation Systems (ITS), vehicle-to-infrastructure (V2I) communication is one of the most important modes. Both ultra-reliable low latency and high-data rate communication are required in the V2I network. In this paper, extensive ray-tracing (RT) simulations are conducted to characterize the channel for mmWave V2I communication in typical urban scenarios in 22-23.6 GHz. Based on the RT results, the path loss, root-mean-square (RMS) delay spread, and the Rician K-factor of the channel are characterized, which guide the design and deployment of V2I communication systems.

This paper focused on differences of vehicle-to-vehicle (V2V) radio channel characteristics in the same region but different traffic density and speeds (congestion and non-congestion) at 5.9 GHz. Continuous measurement campaign was conducted on a city expressway through the complex dense urban area in Wuhan, China. Small-scale channel characteristics including power delay profile (PDP), amplitude fading distribution, K-factor, delay spread and doppler shift were obtained, respectively. Specifically, the cumulative distribution function (CDF) of root mean square (RMS) delay spreads and RMS doppler spreads in non-congestion scenario and congestion scenario were all fitted well with Lognormal distribution. We also found that different intensity of traffic and speed of vehicles have little effect on RMS delay spreads, but have a big impact on RMS doppler spreads. According to estimation outcomes, the V2V channel characteristics in Chinese urban scenario were different from the previous measured results in European cities. All of these conclusions in this paper can provide references to design the wireless communication system for V2V channel.

Design, analysis and implementation of a time-bounded spectrum handoff algorithm for real-time industrial wireless sensor and actuator networks

Recent advances in Artificial Intelligence (AI)-driven wireless communication are driving the adoption of Sixth Generation (6G) technologies in crucial environments such as hospitals. Visible Light Communication (VLC) leverages existing lighting infrastructure to deliver high data rates while mitigating electromagnetic interference (EMI); however, patient movement induces fluctuating signal strength and dynamic channel conditions. In this paper, we present a novel integration of site-specific ray tracing and machine learning (ML) for VLC-enabled Medical Body Sensor Networks (MBSNs) channel modeling in distinct hospital settings. First, we introduce a Q-learning-based adaptive modulation scheme that meets target symbol error rates (SERs) in real time without prior environmental information. Second, we develop a Long Short-Term Memory (LSTM)-based estimator for path loss and Root Mean Square (RMS) delay spread under dynamic hospital conditions. To our knowledge, this is the first study combining ray-traced channel impulse response modeling (CIR) with ML techniques in hospital scenarios. The simulation results demonstrate that the Q-learning method consistently achieves SERs with a spectral efficiency (SE) lower than optimal near the threshold. Furthermore, LSTM estimation shows that D1 has the highest Root Mean Square Error (RMSE) for path loss (1.6797 dB) and RMS delay spread (1.0567 ns) in the Intensive Care Unit (ICU) ward, whereas D3 exhibits the highest RMSE for path loss (1.0652 dB) and RMS delay spread (0.7657 ns) in the Family-Type Patient Rooms (FTPRs) scenario, demonstrating high estimation accuracy under realistic conditions.

Background. Ultra-Reliable Low Latency Communication (URLLC) as a service offered by fifth and sixth generation (5G/6G) wireless systems is a technological response to the needs of various mission-critical applications that require reliable data transmission with low latency. These applications also include Intelligent Transportation Systems services, which, among other things, provide connectivity and autonomous vehicle control. The combination of high reliability and low latency requirements in URLLC usage scenarios creates a security problem for URLLC data transmission that cannot be solved using conventional complex cryptographic methods based on a secret key. The article discusses in detail the approach to using physical layer security mechanisms (physical layer security - PLS) as a powerful alternative to classical cryptographic security methods for URLLC, and also proposes the application of the wire-tap channel concept in URLLC with an analysis of the efficiency that can be achieved for physical layer security. Objective. The aim of the article is to provide an overview of information security solutions in URLLC usage scenarios, as well as to propose a constructive method for information protection for reliable data transmission with low latency without the use of cryptographic mechanisms based on a secret key. Methods. Theoretical research in the field of the branch channel concept was used to create solutions that allow data protection with information-theoretic stability in URLLC usage scenarios for providing IoT, connected car and autonomous driving services. Results. The article examines in detail the data security issues in ultra-reliable low latency communication (URLLC) as a service offered by fifth and sixth generation (5G/6G) wireless systems. It is determined that URLLC is a technological response to the needs of various critical applications that require reliable signal transmission with low latency, and among these applications are Intelligent Transportation Systems services, which, among other things, provide connectivity and autonomous vehicle control. It is shown that the combination of high reliability and low latency requirements in URLLC scenarios creates a security problem for URLLC data transmission that cannot be solved using conventional complex cryptographic methods based on a secret key. The feasibility of using physical layer security mechanisms (PLS) as a powerful alternative to classical cryptographic security methods for URLLC is substantiated. The approach to applying the concept of a wire-tap channel in URLLC is considered in detail, as well as the results that can be achieved for physical layer security, and the influence of code parameters for probabilistic cryptographic transformations in accordance with the concept of a wire-tap channel on PLS URLLC. Estimates of the effectiveness of PLS URLLC for finite block length codes are provided. Conclusions. An effective way to ensure data security for ultra-reliable low-latency physical layer link (PLS URLLC) of fifth-generation 5G wireless systems in the field of connected cars and vehicles of 4-5 levels of automation can be approaches based on the concept of a tapped channel ("wire-tap channel").

Many industrial systems exhibit the nonlinear characteristics. Generally, the structure of the system is taken by feedback closed-loop for the purpose of realising the automatic control of industrial processes. Therefore, the industrial systems are the closed-loop feedback nonlinear systems which have complicated structures. The mathematical models of systems provide the support and basis for the design of the control system and the better control performance. However, it is hard to determine the models of closed-loop feedback nonlinear systems due to the complex structures. The goal of this study is to develop an identification way for a feedback nonlinear system including a forward channel and a feedback channel, where the forward channel is described by a controlled autoregressive model and the feedback channel takes the form of a static nonlinear function. By taking advantage of the least squares optimisation, a recursive least squares algorithm is established and shows its good performance to solve the identification problem for the feedback nonlinear system.

This paper analyses the suitability of the RMS delay spread and coherence bandwidth when characterising system quality-of-service of QPSK operating in a variety of wideband mobile channels. It is demonstrated that the RMS delay spread is unduly affected by the presence of relatively weak signals with large excess delay, limiting it's effectiveness when characterising the time dispersion. The coherence bandwidth is shown to offer a more general dispersion metric. Furthermore it is indicated that the instantaneous system performance is poorly characterised by the dispersion parameters calculated from the discrete power delay profile (such as the RMS delay spread). The instantaneous delay spread incorporates the effects of pulse shaping and the vector summation which occurs in the instantaneous channel impulse response. Consequently, the instantaneous delay spread is demonstrated to provide a better indication of the instantaneous performance than the RMS delay spread.

With the imminent introduction of the 3G systems throughout the world precise cell planning in macrocell, microcell and picocell environments have become equally important. Beside coverage of the basic radio link quality parameter others such as rms delay spread and a measure of the system capacity have become increasingly important. Our contribution addresses the planning inside microcells based on a 3D deterministic ray-tracing propagation tool. It is based on the IHE model (Cichon, 1984) and a simple genetic algorithm (SGA) for the base station location optimization. At this stage the optimization is based on coverage and rms delay spread considerations. Our algorithm has as inputs the delay spread threshold and the minimum field strength. The cost function to be minimized is the number of locations in which the values of these parameters are above the threshold in the case of delay spread, and respectively below the threshold in the case of the field strength.

Industrial automation systems are showing a strong trend towards convergence and networking. Infrastructures and devices with standardized implementations are increasingly being used in the industrial environment where traditionally isolated solutions have been used before. Information security management has become an important concern in the field. We are investigating the challenges of information security management in a modern industrial automation environment.

Most of the accidents like blasts, fire-breakouts in industries occur due to the industrial high temperature and toxic gas leaks. This does significant harm to the machinery, human life, and the environment. At the moment, the people are using traditional the gas-leak detectors which only generate on-site alarms. So, this project proposes industrial environment surveillance and a safety assurance system through which the real-time monitoring of the industrial environment is possible through a cloud storage server (such as Google Drive) and the system is also capable to send the warning to the client or person assigned for supervision through SMS. This low-cost project includes Arduino Mega R3 as an MCU (Microcontroller Unit), DHT11 sensor for temperature and humidity sensing; MQ2, MQ7, and MQ135 gas sensors, ESP-8266 as a WLAN communication module to connect the system with the cloud and GSM module to send SMS depending on the pre-defined threshold to the specified person.

Industrial Wireless Sensor Networks (IWSNs) integrate various types of sensors to measure and control industrial production. However, the unattended open environment makes IWSNs vulnerable to malicious attacks, such as Sybil attacks, which may degrade the network performance. In addition, multipath distortion, impulse noise and interference effects in the harsh industrial environment may influence the accuracy of attack detection. In this paper, we propose a Sybil detection scheme based on power gain and delay spread analysis by exploiting the spatial variability from their channel responses. Specifically, we utilize channel-vectors to represent the sensor features based on the power gain and delay spread extracted from channel response. Furthermore, we develop a kernel-oriented method to distinguish Sybil attackers from benign sensors by clustering the channel-vectors. In addition, to alleviate the impact of industrial noise and interference effects, we design a multi-kernel based fuzzy c-means method to map the extracted channel-vectors into a new feature space such that the dispersive effects on the channel-vectors can be reduced. We also propose a parameter selection method to optimize the employed kernels. The simulation results show that the proposed multi-kernel scheme can achieve high accuracy in detecting the packets from Sybil attackers, and tolerate the dispersive attenuation and interference effects in the industrial environments.