Wavelet-Transform-Based Sparse Code Multiple Access for Power Line Communication

The paper presents a methodology proposal for testing and evaluation of communication systems in Smart Grids, especially for Power Line Communication (PLC) systems. The PLC technology is widely used in power grid as a part of Advanced Metering Infrastructure (AMI) allowing mainly data transfers between a management system at utility and customer-premises smart meters. However, the PLC technology on medium voltage (MV) lines is often used for remote control and monitoring of distribution transformers as well. Since power grid and consequently power lines have different transmission parameters affected by their placement and potentially burdened by interferences, the PLC systems have to be evaluated on site before placed to production. In this paper, authors propose a methodology for long-term benchmarking of the PLC systems using newly developed testing tools. The methodology is subsequently tested on real power grid and a selection of results is presented.

HF Band Power Line Communication (PLC) is rapidly gaining popularity with new network systems not only in the home, but also in places where the number of users is relatively large. Since the PLC uses wide frequency band for data modulation, some coexistence conditions with other services were provided. We investigated the performance of three types of PLC systems, HD-PLC, HomePlug and UPA, under unfavorable conditions such as connecting the PLC modem to the uninterruptible power supply (UPS) outlet or simultaneously using it with a different PLC system. Although violating the proper instructions, each PLC system could still transfer data to some degrees. It was confirmed that UPS and PLC act as a source of noise for the other PLC systems and the degree of interference varies with the PLC systems used.

The use of repeaters (relays) has recently been introduced in power line communication (PLC) systems for long-distance data transfer and thus, it becomes important to analyze the performance of relay based PLC systems. A simplified system model with distance dependent signal attenuation and additive white Gaussian noise may not cover all the factors affecting the data transfer, such as variation in amplitude (fading) and occurrence of impulsive noise. Hence, a more realistic system model with log-normal fading, distance dependent signal attenuation, and a Bernoulli-Gaussian impulsive noise is considered in this paper to study the end-to-end average bit error rate (BER) and the end-to-end average channel capacity of a PLC system equipped with amplify-and-forward (AF) relays. Approximate closed-form expressions of the end-to-end average BER for binary phase-shift keying and the average channel capacity for high signal-to-noise ratio are obtained. The performance of the PLC system with AF relays is found to be superior compared to that of a direct transmission PLC system for fixed transmission power.

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.

Although Power Line Communication (PLC) is not a new technology, its use to support data transmission over low voltage (LV) distribution networks is still the focus of ongoing research. This thesis focuses on the channel modelling and performance evaluation of narrowband (NB) PLC system. First, the channel modelling approaches of PLC are studied. Then, the proposed PLC channel modelling method based on the bottom-up approach for LV narrowband PLC in a frequency band between 9 kHz and 490 kHz is presented. This proposed model employs the transmission and scattering matrix methods to calculate the transfer function of a typical LV PLC network which comprises two common cable types (copper cables and aluminium conductor steel reinforced). Unlike the top-down approaches, this model is scalable as the network complexity increases and can better describe the network behaviour as a function of physical parameters.In addition, the noise characteristics and popular noise reduction techniques of PLC are studied. The major impairment to the PLC is the impulsive noise which is mainly generated by the switching transient in the network. Hence, a new technique is proposed to mitigate the impact of impulsive noise on data transmission over power lines. This proposed technique is an optimal Clipping/Blanking nonlinearity technique which is based on the minimum bit error rate (BER) search. Results obtained from the simulation of this technique demonstrate that performance has been enhanced in the NB-PLC system. The performance of the narrowband PLC system is also evaluated in both physical (PHY) and medium access control (MAC) layers. Since Orthogonal Frequency Division Multiplexing (OFDM) is a suitable modulation scheme for hostile environment of the power line, it is used to evaluate the PHY layer performance. As a result of the PHY layer performance analyses, it is found that the BER performance between neighbouring points in the typical LV PLC network is reasonable, but communication beyond one hop have to rely on upper layer protocols. In the MAC layer performance evaluation of the PLC system, the widely known random access MAC protocol that uses the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) will be utilised. The MAC performance evaluation of the PLC system demonstrates a significant packet loss in LV PLC network even with a light traffic condition due to the noisy channel. Furthermore, the goodput declines abruptly once the individual transmission rate is high enough to block the network. In addition, the simulation results show that the channel errors can be reduced by adjusting the MAC parameters to allow the re-transmissions mechanisms to recoup the lost packets.

The nature of the Power Line Communication (PLC) equipment is complex because it is considered as an information equipment for Electro-Magnetic Compatibility (EMC) standardization, but it is used to inject High-Frequency (HF) and Very High Frequency (VHF) frequency signals on the existing power network which is not designed to guide these frequencies. This PLC system issue leads to some difficulty to finalize EMC standardization of PLC equipment. This paper shows some EMC issues due to the parasitic radiation of HF and VHF PLC systems. An original method using radiofrequency analysis is used to demonstrate that power lines act as antennas for PLC frequencies, as if the PLC system was a radiofrequency system. So, we can define the PLC system as a "not intended radiofrequency system", i.e. a family product which have to comply not only with EMC standards but also with Radio Equipment Directive (RED) system.

Power line communication (PLC) utilizes power lines for the purpose of electronic data transmission. The performance of a PLC system is significantly affected by the additive and multiplicative power line noises; the additive noises are of two types, namely background noise and impulsive noise. Whereas, the multiplicative PLC noise leads to fading in the received signal strength. In this paper, we evaluate the performance of a PLC system over log-normal fading channel under Nakagami-m distributed additive background noise assuming binary phase shift keying modulation scheme. The analysis involving log-normal fading is very complicated. Hence we use a novel gamma approximation to log-normal distribution for our analysis. We evaluate the probability density function of the decision variable. A closed-form expression of the analytical average bit error rate of the considered system is derived. We also compute the diversity order of the considered PLC system. The validity of the derived analytical expressions is closely verified by the simulation results.

The emissions from the power line communication (PLC) system should be investigated for the influence to the electromagnetic environment. The method of moment (MOM) has been studied to estimate the emitted electric field. However, the MOM is difficult to treat the dielectric material of the cable. This paper proposes the method of creating the wire grid model considering the dielectric material of the power line cable. The radius of the wire was determined from the per unit length inductance of the cable. The admittance is inserted between wires to present the effect of the dielectric material, and the value is determined from the admittance calculated by using the FEM based on the two-dimension model. The other admittance was inserted between each wire and ground and the value was also determined from the FEM results. The appliances were presented by T-type network based on the measurement results. The common mode input impedance and radiated magnetic field were measured and compared with the calculated one, and the evaluation indicated that the well agreement was obtained. A simple model of the indoor power line system was constructed and the radiated magnetic field was calculated. The evaluation was indicated that the calculation results almost agreed with the measured one. These results mean that the wire grid model is effective to estimate the radiated electromagnetic field from PLC system.

Unpredictable characteristics of power line communication (PLC) channels seriously affect the performance of the communication systems. Among these unpredictable characteristics, noise is considered to be the main source of errors in data transmission in PLC systems. Unlike conventional communication systems in which noise is usually modeled as additive white Gaussian noise (AWGN), its definition in PLC channels has a more complicated form. In order to design reliable PLC systems, it is essential to understand the features of noise in power line networks. Since the impulsive noise generated by electrical house appliances is one of the most significant noise types in PLC channel, it is very important to analyze these electrical devices with respect to their noise characteristics. In this paper, impulsive noise characteristics of various house appliances are analyzed over the frequency range of 30kHz-50MHz.

This paper introduces the Priority‐Aware Federated Resource Allocation (PAFRA) algorithm, a novel resource allocation strategy designed for power line communication (PLC) systems. Leveraging a federated learning framework, PAFRA optimizes the distribution of limited spectrum resources across multiple nodes within a residential environment. The algorithm integrates a priority‐based time slot allocation to effectively manage subchannel conflicts and employs a Double Deep Q‐Network for local training at each node. This training modality includes comprehensive state, action, and reward configurations to fine‐tune transmission power and subchannel selections. Extensive simulations reveal that PAFRA substantially enhances system throughput, outperforming both traditional numerical optimization methods and contemporary machine learning approaches. Specifically, at a signal‐to‐noise ratio of 30 dB, PAFRA achieves a system throughput of approximately 950 Mbps, marking a 23% improvement over existing approaches. These findings highlight PAFRA's ability to significantly enhance network efficiency while complying with regulatory emission standards, demonstrating its potential to optimize dynamic PLC systems.

Modern hospitals are beginning to adopt E-HEALTH as efficient complements to the traditional healthcare services. To support the E-HEALTH services, a locatable, radiation-free and high-capacity communication system is urgently needed in hospitals. Power line communication (PLC) system can use the ubiquitous power line network to power the light-emitting diode (LED) lights while serving as the backbone network for the indoor visible light communication (VLC) systems naturally. In this paper, an integrated broadband power line and visible light communication systems with OFDM modulation is proposed for the indoor hospital applications. This gives a brand-new solution to replace the conventional wireless communication systems in hospitals.

This keynote discusses the behavior of noise in indoor power line communications (PLC) channels. Some ideas to improve system performance based on the knowledge of PLC noise are also introduced. The power-line noise at an outlet is the sum of noise waveforms produced and emitted to the lines from the appliances connected to the power-line network. In the design and the analysis of wireless communication systems, stationary additive white Gaussian noise (AWGN) is often assumed. In PLC systems, however, the statistical behavior of the man-made noise is quite different from that of the stationary AWGN. The fact that the noise in power-lines is not AWGN is often believed to be a cause of low quality of communications. However, Gaussian is the distribution of the largest entropy, and communications under non-Gaussian noise may achieve better performance if the system is designed to adapt the noise statistics. In other words, PLC systems retain large potential for performance improvement if the behavior of the noise is clarified and taken into account in the system design. For narrow-band indoor PLC, we have a mathematically tractable and accurate model based on experimental measurements. In this model, the noise is expressed as a Gaussian process whose instantaneous variance is a periodic time function. With this assumption and representation, the cyclostationary features of power-line noise can be described in close form formula with a small set of parameters. In wide-band indoor PLC, we have made measurements with high speed sampling (50MHz) with long observation duration (10.4s).

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.

In this paper, we analyze a narrowband power line communication (PLC) system under the influence of additive background and impulsive noises. The background noise is modeled as the Gaussian noise, whereas, the impulsive noise is characterized by the Laplace distribution, in order to satisfy the heavy tail requirement of the impulsive noise density function. Moreover, we model the occurrence of impulsive noise in PLC system with Bernoulli and Poisson random variables. We analyze the performance of considered narrowband PLC system in terms of capacity. Specifically, expressions for average channel capacity are derived in case of Bernoulli-Laplace and Poisson-Laplace impulsive noises. The analytical results are supported by the simulations.

Recently, power line communication (PLC) is receiving attention from academic and industry researchers worldwide. In particular, PLC systems have been largely investigated as a medium for transmitting control signals, diagnostic information, or data measured by sensors in Smart Grid. However, PLC systems face several challenges, such as multipath effects and impulsive noise, which may degrade data communication performance. To surpass such issues we propose CodePLC, a dynamic network coding MAC protocol for PLC. CodePLC relies on a single, yet dynamically chosen, relay node. This node stores and forwards linear combinations of PLC frames, which are then combined on their final destinations. We have evaluated the performance of CodePLC through simulations in a PLC system based on a time division multiple access orthogonal frequency-division multiplexing scheme. Simulation results indicate that, in broadcast transmissions, CodePLC enhances system performance. When compared to a PLC system that does not consider the use of CodePLC, based on a stop&wait MAC layer protocol, our new protocol presents an average of 115% of goodput increase. Moreover, CodePLC reduces the average network buffers occupancy by 112%. Finally, our protocol is capable of reducing the mean end-to-end latency by 400%.