Power Line Communication System Research Articles

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.

Bus network decomposition for fault detection and isolation through power line communication

This paper deals with fault detection and isolation (FDI) in complex embedded wired communication networks. The considered faults are soft faults which do not prevent the communication, but may evolve into hard faults, i.e. short or open circuit. A novel FDI method based on power line communication (PLC) transmission systems is proposed. In these PLC systems, the transmission coefficients between the source and each receiver are estimated for communication purposes using orthogonal frequency division multiplexing (OFDM). Health indicators and residuals are computed by comparing the online estimated transmission coefficients with the reference coefficients. A methodology for dealing with complex networks, such as bus networks, is proposed. It is based on the decomposition of the network into several Y-shaped sub-networks. Each of these sub-networks is monitored to detect the presence of a fault. The FDI method is first validated using real data extracted from a Y-shaped network test bench. Then, the proposed approach is validated on a more complex network using realistic simulated data.

Characterizing Low-Data-Rate Power Line Communication Channels

Electric power lines could, in principle, provide a ubiquitous wired communication network linking electrical loads, power meters, and other devices. This communication infrastructure could unlock new sensing and control capabilities, improving the efficiency and reliability of power system operations. In practice, however, power line communication (PLC) is complicated by both known and variable difficulties related to background noise, signal attenuation, and unknown line impedances. This article develops instrumentation that characterizes and verifies line characteristics for PLC applications, especially for demand response and control applications. This instrumentation provides a window to key variables that affect communication on a local power distribution network. With these measurements, limits on PLC communication can be verified before an installation, and a PLC system may also be adaptively tuned to measurements of the current local environment. Field experiments in a challenging microgrid and a 24-floor apartment building demonstrate an appropriately tailored PLC system communicating reliably in locations where conventional PLC fails.

Three-User Cooperative Dual-Stage Non-Orthogonal Multiple Access for Power Line Communications

We present a cooperative, dual-stage (DS) non-orthogonal multiple access (NOMA) scheme for power line communication (PLC) systems, where three PLC modems are served in two time slots. The network consists of a source (S) modem, two relay (R) modems and a destination (D) modem. In each of the two time slots, S communicates with one R using NOMA, and the other R communicates with D using the decode-and-forward technique. We consider both scenarios where a direct link may or may not exist between S and D. We derive expressions for the approximate average sum rate and overall outage probability of the network. Next, we formulate an optimization problem to find the optimal power allocation coefficients at S, such that the sum rate is maximized. We establish the accuracy of our approximations using Monte Carlo simulations. Furthermore, we show that our scheme outperforms the two-user single-stage and the DS schemes, and the three-user NOMA scheme proposed in the earlier literature, in terms of sum rate and outage probability.

Performance Analysis of Power Line Communication System for Massive Indoor IoT Applications

This study explores the utilization of low-voltage indoor power line communication (PLC) technology within the framework of a split centralized radio access network (C-RAN) architecture, aimed at enhancing 5G indoor mobile coverage for the Internet of Things (IoT). A primary focus of this investigation is the comprehensive evaluation of the system’s performance in terms of radio and access latency. Several critical variables come into play, including available bandwidth, the chosen transmission technology, and the number of wireless IoT devices within the network. An analytical model, employing queuing theory, Markovian models, and stochastic geometry, is formulated to assess the radio-access delay spanning the air interface and the innovative PLC-based front-hauling system proposed in our previous study. The precision of this model is validated through simulations, ensuring that the proposed system effectively meets the stringent latency constraints required by eCPRI, thus contributing to the improvement of 5G indoor mobile coverage for the IoT network.

Design and Evaluation of a 180 nm Powerline Communication ASIC for Harsh Environment

Modern complex drilling systems contain communication nodes like sensors, actuators, and controllers, spread along the lower end of a drill string. Here, temperatures of more than 150°C and pressure levels up to 200MPa are present. These environmental conditions and mechanical shocks, are extremely challenging for the reliable use of electronic components. A powerline communication system is designed and evaluated to establish a robust communication channel with low amounts of wiring. This system can operate on highly distorted physical transmission channels by adding redundancy at the sender that can then be used to correct errors at the receiver. In order to synchronize the real-time clocks among different powerline stations, a new preamble extension approach that enables precise time synchronization between multiple bus nodes is added. After design and verification, this system was manufactured in XFAB 180nm Silicon-On-Insulator (SOI) technology allowing operating temperatures of up to 175°C. The die size is 5.25 mm × 5.25 mm and contains a complete HomePlug 1.0 communication stack with an environment for boot, interfacing, and debugging. Its data rate reaches 6.1Mbit/s using the fastest transmission mode and the theoretical maximum of 0.55Mbit/s in the robust OFDM (ROBO) mode, which is of particular interest for harsh environment applications. After verifying the fabricated die, a Printed Circuit Board (PCB) for climate chamber evaluation was designed and fitted. Measurements in this chamber carried out a maximum ambient temperature of 190°C for communication with a minimum self-heating of the die of 20°C measured at room temperature. In combination, this is 35°C above the specification of the technology process. The timing synchronization evaluation showed a precision of 55.6ns over the temperature range from -30°C to 185°C, which is as low as 1.5 clock cycles. Power measurements of up to 190°C have shown an average power consumption increase of only 63μW/K below 150°C and a maximum increase of 394μW/K above 150°C. To the best of the authors’ knowledge, this is the first high-temperature evaluation of a powerline communication ASIC, which is particularly designed for a drilling system’s harsh environment.

A Notch Filter-Based Coupling Circuit for UNB and NB PLC Systems

This paper introduces an analog notch filtering-based coupling circuit for receivers in ultra-narrowband and narrowband power line communication systems, which are connected to low-voltage electric power grids. It is composed of a twin-T notch analog filter, which is responsible for imposing a significant attenuation on the main frequency (i.e., f0∈{50,60} Hz) in cascade with an elliptic low-pass analog filter, designed with a 3 dB cut-off frequency of fc≫f0. For f0=60 Hz and fc=2 MHz, the prototype of the analog notch filtering-based coupling circuit attains attenuation values of 22 dB and less than 2 dB at the main frequency and in the rest of the frequency bandwidth, respectively, when practical scenarios are considered. Lastly, it shows that the analog notch filtering-based coupling circuit is more effective than a typical capacitive coupling circuit when frequencies lower than 3 kHz are considered for data communication and sensing purposes.

Optimal Fractional Pilot Duration for a Correlated Receive Diversity Reliable PLC System With Imperfect CSI in Nakagami-m Noise Environment

The paper presents a single-input-multiple-output-based power line communication (PLC) system employing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${M}$ </tex-math></inline-formula> -ary phase-shift keying signaling for data transmission, with the channels subjected to correlated Rayleigh multipath channels and corrupted by Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${m}$ </tex-math></inline-formula> noise environment. The channel state information for the PLC system is obtained prior to data transmission using the minimum mean square error estimation technique, utilizing which a maximum likelihood-based sub-optimal receiver is proposed. The closed-form expression for the symbol error probability (SEP) is derived, for the cases of the channels following exponential and uniform correlations, using a characteristic function approach. Furthermore, the optimal pilot symbol duration is obtained to maximize the normalized error-free data rate of the system, which simultaneously saves on the energy of the pilot symbols and reduces the SEP of the data symbols. The numerical results demonstrate the effect of variation of different system parameters such as signal-to-noise ratio, channel diversity, pilot symbol quality, correlation factor, and the noise shape parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${m}$ </tex-math></inline-formula> of the background noise on the maximum normalized error-free data rate and thereby providing various insights into the system design for a reliable and energy-efficient PLC system with imperfect knowledge of the channels at the receiver.

Inductive coupling-based narrowband PLC systems for overhead MV power distribution networks: New insights

This paper advances the investigation of the adequacy of inductive coupling-based narrowband power line communication (PLC) systems in overhead medium voltage power distribution networks (MV-PDNs). Relying on raw data obtained from a measurement campaign which was carried out in urban and rural feeders in the south region of Brazil, it shows that overhead MV-PDNs may be a challenging data communication media when considering inductive coupling devices since the level of insertion losses associated with the coupling process is relevant. Also, the presence of significant loads between the source and destination nodes can severely degrade loops of currents, which are necessary to perform data communication in an inductive coupling-base PLC system, resulting in an erasure data communication media. For the reliable links (i.e., without erasure), the performance analysis shows that PLC channel impulse responses and additive noises can be respectively modeled as time-invariant systems with a quasi-flat channel frequency magnitude and white Gaussian random processes in urban and rural areas. Last but not least, an attenuation model and achievable data rates are discussed for the reliable links.

Optimal Multi-Level Amplitude-Shift Keying Modulation for a Reliable Channel Magnitude Detection-Based Receive Diversity Powerline Communication System

The implementation of a coherent powerline communication (PLC) receiver increases its hardware complexity and energy consumption, which can be tackled by a non-coherent receiver. However, this reduces the reliability of the PLC systems. To meet this trade-off, a novel energy-efficient receiver structure is proposed in this study that exploits the knowledge of the channel magnitude of a receive diversity PLC system. The transmitter employs multi-level amplitude-shift keying (ASK) modulation for data transmission via the PLC channels subjected to Rayleigh multipath phenomenon and corrupted by additive Nakagami-m background noise, which would lead to a superior performance as compared to other modulation schemes owing to the channel magnitude-based proposed receiver. Utilizing the receiver structure, closed-form expression for symbol error probability (SEP) and its asymptotic expression at a high average signal-to-noise ratio (SNR) are derived using a characteristic function approach. Furthermore, to achieve the simultaneous design of an energy-efficient modulation scheme and a reliable PLC system, optimal ASK signaling levels are obtained with a constraint on the total available energy at the transmitter end. The analytical relation of the derived optimal multi-level ASK constellation with the traditional ASK constellation is obtained at high SNR values. The proposed channel magnitude-based receiver is found to achieve full diversity order and numerical results presented provide various insights towards the design of the energy-efficient PLC system.

Research on ultra-reliable and low-latency secure transmission of distribution monitoring communication system

In the smart distribution network scenario, we investigate the physical layer security performance of power line communication in FBL. The results show that the system secure transmission rate increases with increasing channel block length and eventually converges to a constant value. Compared with the traditional SE maximization algorithm based on FBL, the total secrecy rate is improved by about 13%. Compared with the traditional linear precoder (ZF), the secrecy rate is improved by about 30%. Therefore, the proposed scheme is superior in supporting the power line communication system based on FBL.

A Power-Line Communication System Governed by Loop Resonance for Photovoltaic Plant Monitoring

Within this paper, a PLC system that takes advantage of the loop resonance of an entire DC-PV string configured as a circular signal path is developed and implemented. Low cost and extremely simple transceivers intended to be installed within each PV module of a string have been designed and successfully tested. In addition, an anti-saturation coil has been conceived to avoid saturation of the core when the entire DC current of the string flows through it. Bi-directional half-duplex communication was successfully executed with up to a 1 MHz carrier frequency (150 kbps bitrate), using a simple ASK modulation scheme. The transmission and reception performance are presented, along with the overall system cost in comparison to the previous literature.

On Power Line Positioning Systems.

Power line infrastructure is available almost everywhere. Positioning systems aim to estimate where a device or target is. Consequently, there may be an opportunity to use power lines for positioning purposes. This survey article reports the different efforts, working principles, and possibilities for implementing positioning systems relying on power line infrastructure for power line positioning systems (PLPS). Since Power Line Communication (PLC) systems of different characteristics have been deployed to provide communication services using the existing mains, we also address how PLC systems may be employed to build positioning systems. Although some efforts exist, PLPS are still prospective and thus open to research and development, and we try to indicate the possible directions and potential applications for PLPS.