Power Line Communication System Research Articles

Jamming precoding in AF relay-aided PLC systems with multiple eavessdroppers

Enhancing information security has become increasingly significant in the digital age. This paper investigates the concept of physical layer security (PLS) within a relay-aided power line communication (PLC) system operating over a multiple-input multiple-output (MIMO) channel based on MK model. Specifically, we examine the transmission of confidential signals between a source and a distant destination while accounting for the presence of multiple eavesdroppers, both colluding and non-colluding. We propose a two-phase jamming scheme that leverages a full-duplex (FD) amplify-and-forward (AF) relay to address this challenge. Our primary objective is to maximize the secrecy rate, which necessitates the optimization of the jamming precoding and transmitting precoding matrices at both the source and the relay while adhering to transmit power constraints. We present a formulation of this problem and demonstrate that it can be efficiently solved using an effective block coordinate descent (BCD) algorithm. Simulation results are conducted to validate the convergence and performance of the proposed algorithm. These findings confirm the effectiveness of our approach. Furthermore, the numerical analysis reveals that our proposed algorithm surpasses traditional schemes that lack jamming to achieve higher secrecy rates. As a result, the proposed algorithm offers the benefit of guaranteeing secure communications in a realistic channel model, even in scenarios involving colluding eavesdroppers.

Emissions generated by electric vehicles in the 9-500 kHz band: Characterization, propagation, and interaction

Electric Vehicle Charging Processes (EVCPs), due to the involved power electronics with high-switching frequencies, generate high-amplitude emissions that could have a negative impact on Power Quality (PQ) and Narrowband Power Line Communications (NB-PLC) systems. In this context, this paper deals, first, with the frequency and time characterization of the disturbances generated by four EVCPs in the 9-500 kHz frequency range. The study is based on measurements carried out in a controlled Low Voltage (LV) grid. For this purpose, a novel procedure for the frequency and time characterization is proposed. The frequency characterization is based on the calculation of a set of parameters, which allows evaluating not only the amplitude of the disturbances in the frequency band under analysis, but also their spectral distribution. The time variability is characterized by means of a Fast Fourier Transform (FFT) analysis that leads to a simplified model to evaluate the time-dependent behavior of the disturbances, which shows a sub-cycle periodic pattern of the emissions in the frequency band of interest. Second, the propagation of the previously characterized emissions is analyzed, concluding that they propagate several meters through the LV grid. Although in most cases the disturbances are attenuated with distance, there might be resonances that lead to higher amplitudes at an electrical point distant from the source of the emissions. Finally, the influence of the simultaneous charging of several EVs is studied. The results show that, in general, the amplitudes correspond to the superposition of the individual disturbances, in addition to intermodulation products due to the switching frequencies of the inverters.As a conclusion, the high amplitude time-varying emissions, together with their capacity for propagation and interaction, are a matter to be analyzed due to their influence on PQ and their potential degradation of the performance of PLC in the frequency band from 9 kHz to 500 kHz.

Battery configuration dependence to power line communication using high-order quadrature amplitude modulation

Power line communication (PLC) within future smart batteries facilitates the communication of high fidelity sensor data between smart cells and external systems, with application areas including intelligent vehicles and smart grids. This interconnected PLC system of smart cells will enhance cell utilisation and safety through cell-to-cell coordination at a system level, leveraging the existing bus bar within the battery and eliminating the need for additional wire harnesses. This paper studies the performance of a PLC system operating at carrier frequencies of 10MHz to 6GHz within four distinct configurations of lithium-ion batteries. This assessment focuses on changes in scattering parameters and data transmission error ratios. Furthermore, quadrature amplitude modulation (QAM) orders of up to 1024 are investigated for their viability within such environments. The results indicate that the addition of cells in parallel increases error ratios with high-order QAM, and that this effect varies substantially with carrier frequency. Using QAM increases data throughput, allowing for data transfers within large-scale battery systems without PLC bus bandwidth saturation. A prospective centre frequency of 3650MHz allows for a wide bandwidth of 300MHz and 1024-QAM with little signal attenuation and data error. At this frequency, the need for signal repeaters and higher signal output power is reduced. These results are used to determine the most suitable arrangement of cells within a smart battery with consideration of the PLC performance. The preliminary performance of a large-scale battery system with PLC in-situ could be derived from the findings in this research based upon the four battery configurations tested.

Design and Implementation of Drive and Control System for Ultrasonic Motor over Power Line Communication

In this study, remote control application of an ultrasonic motor (USM) has been achieved over the power line communication (PLC) system. Fast, practical, affordable and effective operating mode is essential for the USM. This study aimed to develop an original, efficient, effective and economical method. Drive and control of USM control has been succeeded with the developed PLC control system. A two-phase high-frequency inverter, a power line transmitter, and a power line receiver circuits have been designed to drive and control of the ultrasonic motor. Required measurements are acquired from the power line to select the most suitable communication frequency and coupling circuit impedance for the PLC system. For the communication frequency and impedance value measurements the receiver and the transmitter circuits have been designed. The PLC-controlled system has been tested for different operating conditions of the ultrasonic motor. USM control has been accomplished over the existing power line without using extra cables and interfaces for communication. The obtained results show that the PLC-controlled system is practical, reliable, cost-effective, and feasible for the remote control of the USM. This research contributes a new and essential perspective for the PLC-based remote control studies in addition to the USM drive and control strategies.

Adaptive overcurrent protection scheme coordination in presence of distributed generation using radial basis neural network

The operational performance of conventional overcurrent protection relay coordination connected to a distribution network is adversely affected by the penetration of distributed generators (DG) at different buses in the network. To address this problem, this paper proposes a novel adaptive protection coordination scheme using a radial basis function neural network (RBFNN), which automatically adjusts the overcurrent relay settings, i.e., time setting multiplier (TSM) and plug setting multiplier (PSM) based on the penetration of DGs. Short circuit currents and voltages measured at different buses are acquired using the remote terminal units (RTU) connected to different buses within the terminal network. Communication between the various remotes and local end station RTUs is through hybrid communication systems of fiber optic and power line communication system modules. The new adaptive overcurrent protection scheme is applied to the IEEE 33-bus distribution network with and without DGs, for single and multi-DG penetration using both the ETAP and MATLAB software. The simulation results show the proposed scheme significantly improves the protection coordination.

Ergodic Capacity of Power Line Communication System for Applications of Power Distribution Networks with Amplify- and- Forward Relaying

Ergodic Capacity of Power Line Communication System for Applications of Power Distribution Networks with Amplify- and- Forward Relaying

Extending device noise measurement capacity for OFDM-based PLC systems: Design, implementation, and on-field validation

Noise measurement in power line communication (PLC) systems is a common activity performed by grid operators for network tuning operations. Usually, these measurements are carried out with portable devices that have a fixed sensing and storage capacity.In this context, this paper presents a software-only solution for enhancing the performance of noise measurements in PLC systems. In detail: (i) we extend the measurement capacity in terms of the maximum number of samples that can be detected continuously, by using a machine learning (ML)-powered low complexity algorithm; and, (ii) we reduce the discontinuity period between successive measurements. This latter feature enables the possibility of collecting more continuous data. To show the viability of our proposal, we conducted a field measurements campaign to measure the scheme’s accuracy and the measurement capacity extension ratio (MCER). The introduced approach is able to increase the MCER by up to 8 times, in the considered PLC environments, with an accuracy above 90%. While the proposed approach has a clear application – improving current devices’ noise measurements capability without requiring costly hardware upgrades –, the technique herein shown has a general applicability, and could hence pave the way for further applications in related fields.

Performance of polar codes with low complexity cyclic redundancy check aided bit‐flipping for successive cancellation list decoding over power line channels

SummaryPower lines have complex transmission characteristics and noise interference when used as information transmission channel, thus limiting their data‐carrying rate and reliability. Impulsive noise is the most dominant factor degrading the performance of communication systems over power lines. To combat the impulsive noise, polar codes are introduced into the orthogonal frequency division multiplexing (OFDM)‐based power line communication (PLC) system. Because the successive cancelation list bit‐flip (SCLF) decoding algorithm of polar codes has high decoding complexity, a low complexity segmented cyclic redundancy check (CRC)‐aided SCLF decoding is proposed to improve the decoding performance. The decoding process can be terminated early with segmented CRC, which can reduce the bit‐flip decoding complexity significantly with short and medium block lengths. Experimental results demonstrate that for various configurations, the proposed decoder outperforms the traditional CRC‐aided SCL decoder in terms of decoding performance and complexity, and the suggested polar codes‐based OFDM‐based PLC system can reduce the bit error rate of the system in the presence of impulsive noise.

Secrecy Analysis of DCSK-Based PLC Systems With Multiple Eavesdroppers

In the past two decades, chaotic modulation schemes have drawn much attention for their significant advantages over other traditional modulation techniques. One of the noticeable advantages is the capability of providing secure communication in the presence of an eavesdropper. In this article, we study the physical layer security (PLS) performance of low-frequency power line communication (PLC) systems against multiple eavesdroppers by employing differential chaos shift keying based modulation technique. A wiretap power line channel model is investigated by considering two different cases: 1) when all the channels are assumed to be independent and identically distributed (IID) following Log-normal distribution; and 2) the wiretap channels are considered to be identical but correlated Log-normally distributed and independent of the main channel. Contemporaneously, the Bernoulli-Gaussian random process models the PLC noise. Further, a comprehensive PLS study of the considered PLC system is characterized in terms of the average secrecy capacity, secure outage probability, and strictly positive secrecy capacity. We also propose an algorithm to maximize the secrecy throughput under security and reliability constraints. Moreover, to obtain essential insights, we reveal the impact of various crucial parameters onto the proposed system.

On the Performance of the UAV RIS-Assisted Dual-Hop PLC-RF Systems

In this work, we propose an unmanned aerial vehicle (UAV)-based reconfigurable intelligent surface (RIS)-assisted dual-hop power line communication and radio frequency (PLC-RF) system, in which a UAV-based RIS (URIS) located in the sky forwards signals from the relay to the terrestrial user. More specifically, we assume that the PLC channel suffers from a log-normal distribution, and the URIS-assisted RF link follows the Rician distribution. With the amplify-and-forward (AF) and decode-and-forward (DF) relaying models, the closed-form expressions for the outage probability and average bit-error-rate are derived. In addition, by taking into account the hardware impairments, the outage probability of the non-ideal hardware system is derived. Finally, the Monte Carlo simulation verifies the analytical results, which demonstrates the effect of impulsive noise and the number of the reflecting surface units on the system performance.

Modeling of Burst Impulse Noise Errors in an In-House M-QAM-Based Power Line Communications Channel Using the Fritchman-Markov Model.

Within the power line communication (PLC) network, a large number of electronic devices are connected, and environmental factors can cause unusual behavior, leading to high-amplitude impulse noise in the received signal and, as a result, packet losses and burst errors in the data that are sent. Burst errors make it difficult to send data over power line channels efficiently and accurately. Analyzing error patterns with intelligent techniques can provide valuable insights into data transmission efficiency, enhance transmission quality, and optimize PLC systems. This research proposes a three-state Fritchman-Markov chain-based power line communication error model and develops a software-defined PLC system. The goal is to analyze and model the system's statistical error process. The PLC system's fundamental error pattern is deduced from the transmission and reception of data on our software-defined (SD) PLC platform. The system is designed with multi-state quadrature amplitude modulation (M-QAM) data transmission and reception techniques. An error pattern consisting of 50,000 bits is obtained by comparing the bits transmitted with those received using the in-house M-QAM-based PLC transceiver system. The error characteristics of the newly developed M-QAM SD-PLC system are precisely modeled using the error model. Examining the burst error statistics of the reference error sequences of the SD-PLC system and the three-state Fritchman-Markov error model reveals striking similarities. According to the results, the error model accurately represents the error characteristics of the developed M-QAM SD-PLC system. The proposed three-state Fritchman-Markov chain-based error model for PLC has the potential to provide a comprehensive understanding of the error process in PLC. Additionally, it can assess error control strategies with less computational complexity and a shorter simulation time.

The Effect of Spread Spectrum Modulation on Power Line Communications

Interference in Power Line Communication (PLC) is examined in this paper. PLC is a wired communication technology that provides communication and data transmission over the existing electrical network. It uses the electrical wiring in buildings or the electrical grid to transmit data signals between devices, rather than using dedicated communication cables or wireless signals. Many applications employ PLC technologies, which have the benefit of leveraging existing power connections for both power and data transfer, reducing cost and complexity. These interactions may be observed in contemporary smart grids and automobile power networks, where lengthy cables, switching power supplies and communication links all work together but exacerbate Electromagnetic Interference (EMI) problems. This research examines the effects of spread spectrum methods used to reduce EMI from power converters on PLC systems. Spread Spectrum Modulation (SSM) and its three variants, Sine, Random and Sawtooth, are frequently employed to meet the requirements of electromagnetic compatibility, however, there are some repercussions that may be detrimental to the converter or the rest of the electrical network. These outcomes occur for various modulation algorithm settings and at various frequencies. Measurements are made utilising the Frame Error Rate (FER) value provided by the PLC link system to ascertain the interference produced by a Silicon Carbide (SiC)-based DC-DC converter in order to investigate these concerns and standardise an assessment approach. To examine the effect of SSM on reducing EMI in the frequency domain, the peak index of a CISPR-16 EMI receiver is used.

Two-Wire Power Line Microwave Communication Using Low-Loss Modes

A closed-form solution for the common and differential modal currents induced on a pair of infinitely long parallel conductors by a source, field coupled to a power line, is derived. For lossy conductors, the current consists of a continuous spectrum of radiation modes and (for the common mode) a modified low-loss Sommerfeld–Goubau (SG) mode and (for the differential mode) a quasi-TEM mode. This model is used to investigate the influence of a parallel conductor on microwave power line communication systems. When the complete current spectrum is used, it is shown that the SG mode is not the primary reason why low-loss communication is possible on power lines for distances on the order of 100 m. Nevertheless, and consistent with previous research, microwave communication using power lines has advantages over free space communication, and for typical parameters, the performance of these systems can be enhanced if the power line contains more than one conductor.

Method for Digital Cancellation of System Interference in a Full-Duplex Power Line Communication System

Every year the number of IoT devices is growing, which gives a boost to development of such technology as Power Line Communication (PLC). The term PLC refers to the use of a power supply circuit to transmit data. Full-duplex technology can be applied to increase the data transfer rate in a PLC. The difficulty in using a full duplex is the need to suppress the transmitter’s own signal (interference signal). Analog cancellation and digital cancellation are used for this purpose. Common algorithms for digital cancellation are adaptive algorithms. In this paper adaptive algorithms such as Particle Swarm Optimization (PSO) and Recursive Least Squares (RLS) are considered and a modification of the classical RLS is proposed. The proposed algorithm uses precalculated weight coefficients together with periodic reinitialization of the filter. This avoids the influence of significant changes in the input signal on the further process of filter adaptation and provides the highest level of echo suppression. The proposed algorithm provides an improvement of parameters such as Error Vector Magnitude (EVM) and Signal-to-Interference Ratio (SIR) in comparison with classical RLS and PSO, according to the results of the study.

A novel online monitoring method of ground fault in tree form distribution networks based on power line carrier devices

The distribution network can continue to operate for a short time once a single-phase grounding fault arises, but if the defect is not monitored and corrected right away, it might cause serious harm. However, the bulk of fault monitoring algorithms struggle to identify faults when applied to complex distribution networks with a tree structure. In this article, a fault online monitoring method based on power line communication equipment is proposed. The method identifies the fault by monitoring the change of channel frequency response (CFR) of the distribution network in real-time, locates the fault branch by comparing the change amplitude of CFR of different receiving devices, calculates the impedance amplitude of the fault branch, and combines the relation between impedance and distance to further realize the accurate location of the fault point. A large number of simulations show that the method is accurate and stable, and can effectively monitor both high and low-resistance ground faults. Under the simulation conditions without considering signal interference, the fault branch detection accuracy reaches 100%, and the average error of fault distance localization is 19.38 m (1.98%). Compared with other methods, this method is highly applicable, with good real-time performance and high positioning accuracy.

In-band full-duplex MIMO PLC systems for relaying networks

In Power Line Communications (PLC), there are regulatory masks that restrict the transmit power spectral density for electromagnetic compatibility reasons, which creates coverage issues despite the not too long distances. Hence, PLC networks often employ repeaters/relays, especially in smart grid neighborhood area networks. Even in broadband indoor PLC systems that offer a notable data rate, relaying may pave the way to new applications like being the backbone for wireless technologies in a cost-effective manner to support the Internet-of-things paradigm. In this paper, we study Multiple-Input Multiple-Output (MIMO) PLC systems that incorporate in-band full-duplex functionality in relaying networks. We present several MIMO configurations that allow end-to-end half-duplex or full-duplex operations and analyze the achievable performance with state-of-the-art PLC systems. To reach this analysis, we get channel realizations from random network layouts for indoor and outdoor scenarios. We adopt realistic MIMO channel and noise models and consider transmission techniques according to PLC standards. The concepts discussed in this work can be useful in the design of future PLC relay-aided networks for different applications that look for a coverage extension and/or throughput: smart grids with enhanced communications in outdoor scenarios, and “last meter” systems for high-speed connections everywhere in indoor ones.

Performance Analysis of Orthogonal Multiplexing Techniques for PLC Systems with Low Cyclic Prefix Length and Symbol Timing Offset.

This paper investigates the degradation caused by interference resulting from cyclic prefix violation and symbol timing offset in narrowband power line communication systems. In this sense, it presents a unified formulation from which Hermitian symmetric orthogonal frequency division multiplexing (HS-OFDM), orthogonal chirp division multiplexing (OCDM), single-carrier cyclic prefix (SCCP), and orthogonal time-frequency division multiplexing (OTFDM) can be easily derived. The paper then provides closed-form expressions for quantifying the aforementioned interference in the presence of a frequency domain equalizer. The numerical analyses exhibit the performances of these schemes under various data communication conditions, such as the availability of channel state information, the presence or absence of interference, modeling of additive noise as a white or colored Gaussian random process, frequency domain equalizer type, and the use of bit and power allocation techniques. The closed-form expressions and performance analyses regarding achievable data rate and bit error probability provide guidance for dealing with distinct constraints in narrowband power line communication (PLC) systems using the HS-OFDM, OCDM, SCCP, or OTFDM scheme. Lastly, the unified formulation and results obtained motivate the design of multi-scheme transceivers.

Channel estimation for OFDM-based indoor broadband power line communication systems

State-of-the-art indoor broadband power line communications (PLC) systems use orthogonal frequency division multiplexing (OFDM) signals with constellations up to 10 bits/symbol, which makes channel estimation a key aspect. This paper focuses on the initial channel estimation used in the payload, which might be further adapted by means of a decision-directed strategy. This initial estimate has to be computed on a per-frame basis and can be accomplished from the preamble, the header symbol (assuming that it has been correctly decoded) or from a combination of both. This work proposes simple channel estimation techniques for this problem and derives their most appropriate parameters. They are compared with the linear minimum mean squared-error (LMMSE) estimator and others commonly used in wireless scenarios by considering both their performance and computational complexity. The factors limiting the performance of the estimators based on the preamble and the header symbols are analyzed and the implications of the differences between PLC and wireless channels, such as the absence of fading, in the design of estimation techniques that require knowledge of the channel statistics are discussed. A performance analysis of the considered techniques is accomplished in a set of 171 measured indoor PLC channels. Obtained results indicate that estimators from the header perform better than those based on the preamble symbols and we provide a computationally simple estimator that gives nearly optimum performance by combining estimates from both the preamble and the header symbols.

Noise Measurement, Characterization, and Modeling for Broadband Indoor Power Communication System: A Comprehensive Survey

A thorough study of the literature suggests that greater attention has to be paid to power line noise measurements, characterization, and modeling. Several studies show that significant differences do exist, and the findings are somewhat conflicting. This may be attributed to the diverse environment under investigation, which includes volatile noise sources, differences in electrical grid structure from country to country, topology, and unknown power cable characteristics. An in-depth analysis of the approaches for measuring, characterizing, and modeling noise, as well as the descriptions of relevant components, and the environment needed to carry out the measurements, is presented. This review serves as a roadmap for academics and engineers in the deployment of power line communication systems.

Power Optimization of a Three-Node Two-Way Relay-Assisted Power-Line Communication System

A smart grid system requires two-way communication links. Because power-line infrastructure is widely available, power-line communication (PLC) is preferred as the communication technology in smart grid systems. A power-line, on the other hand, was not designed to carry data and thus suffers from disturbances that attenuate the transmitted signal. Therefore, it is beneficial to provide spatial diversity to improve the system performance. Optimal power allocation has always been an issue to be solved in relay-aided communication systems. Using a two-way multicarrier relay configuration, this paper investigates power optimization of a relay-assisted PLC system with the consideration of the quality of service (QoS) constraints. Further, we investigate the combination of half-duplex and full-duplex nodes. Since the QoS constrained power allocation problem is highly non-convex, an alternating optimization (AO) algorithm is proposed to decompose the optimization problem into sub-problems. The AO algorithm is an iterative algorithm where it uses the newly obtained parameters (e.g., power) to find a new set of other parameters. Simulation results show that the proposed system successfully reduces the total power required by the system compared to the conventional bidirectional direct transmission (BDT) system and the relay-assisted two-way information exchange (R2WX) system under the same QoS requirement.