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Small cells are low-power and low-range radio access nodes that can be used to increase network capacity in reduced areas with high traffic demand and to provide coverage to small isolated zones. As their number is expected to be very high, connecting them to the aggregation point in a cost-efficient manner is a key challenge, and there is consensus that none of the current technologies is valid for all scenarios. Since lamp-posts are one of the most convenient locations for outdoor small cells, this work analyzes the use of power line communications (PLC) over outdoor public lighting networks (OPLN) as a backhaul technology for outdoor small cell deployments. To this end, the characteristics of the PLC channels established in OPLN are firstly assessed. The analysis combines noise measurements performed in existing OPLN and channel responses obtained from a multiconductor transmission line (MTL) model. The attenuation, delay spread and spatial correlation of the multiple-input multiple-output (MIMO) channels are investigated and their influence in the physical layer parameters of PLC systems is discussed. Afterward, the performance achieved by state-of-the-art PLC systems is assessed. To this end, estimations obtained by means of simulations and measurements taken in actual networks are included. Data throughput achieved by PLC systems based on the ITU-T G.hn standard, as well as the expected improvements obtained by $3\times 3$ MIMO systems, are given. Results indicate that PLC can be an interesting technology for coverage-driven small cell deployments with backhaul length shorter than 150 m, offering throughput values similar to existing Sub-6 GHz wireless solutions in non-line-of-sight (NLOS) conditions and wired ones like G.fast.

In-band full-duplex (IBFD) is an attractive solution for increasing the throughput of Power Line Communication (PLC) systems. In IBFD, each network node is allowed to transmit and receive simultaneously in the same frequency band. This paper discusses the importance of defining figures of merit to analyze IBFD performance, which is often forgotten by the literature that addresses IBFD from a pure system level and signal processing perspective. This is because in IBFD hardware-related aspects are of great importance. The focus is then given to the first self-interference (SI) cancellation stage, namely the analog coupling and self-interference cancellation stage (ASICS). Two architectures are considered. A detailed analysis is offered by taking into account circuit-level aspects. A broadband multiple conductor PLC scenario is assumed to enable multiple-input multiple-output (MIMO) IBFD communication. The first considered architecture performs SI subtraction exploiting operational amplifiers. The second proposed architecture exploits the characteristics of a three ports magnetic circuit together with a signal generator to remove the SI. Design, analysis, and hardware realization of these circuits have been done to compare and show the practical feasibility of the ASICS for PLC, well known to be challenged by its line impedance matching problems and severe frequency selective channel characteristics. This paper is the first documented contribution of the IBFD ASICS for $2\times 2$ MIMO broadband PLC physically realized and tested in the field.

Smart Grid es un nuevo concepto que busca articular los sistemas de energía eléctrica y de comunicaciones como un sistema unificado para la optimización del consumo energético en el mundo, en donde una de las tecnologías más aceptadas para la transmisión de información en entornos residenciales es Power Line Coomunicatios (PLC). El objetivo del presente artículo consiste en proponer un modelo soportado en teoría de colas, que permita evaluar el comportamiento del tráfico multiclase una red HAN (Home Area Network) bajo el estándar HomePlug AV (HPAV), el cual es uno de los estándares más importantes de la tecnología PLC. Acorde con los resultados obtenidos, el modelo propuesto permite estimar parámetros tales como tiempos de llegada, tiempos de espera en cola, tiempos de atención, probabilidad de pérdida de paquetes, throughput, número de paquetes perdidos, entre otros valores relacionados con el rendimiento de la red. Aunque el modelo puede ser considerado de gran ayuda para trabajos de investigación relacionados con las comunicaciones sobre PLC, podría ser combinado con otras técnicas de análisis más avanzadas, a fin de obtener resultados más profundos y en contextos más complejos. Smart Grid is a new concept that seeks to articulate electric power and communications systems as a unified system for the optimization of energy consumption in the world, where one of the most accepted technologies for the transmission of information in residential environments is Power Line Co-communications (PLC). The objective of this article is to propose a supported model in queue theory, which allows the evaluation of multiclass traffic behavior of a HAN (Home Area Network) network under the HomePlug AV (HPAV) standard, which is one of the most important standards of PLC technology. In accordance with the results obtained, the proposed model allows estimating parameters such as arrival times, queuing times, attention times, probability of packet loss, throughput, number of packets lost, among other values ​​related to the performance of the net. Although the model can be considered a great help for research papers related to PLC communications, it could be combined with other more advanced analysis techniques, in order to obtain deeper results and in more complex contexts.

In the last few decades, the use of power converters has become essential in the smart grid environment. Consequently, this leads to the presence of a high-level of conducted electromagnetic interference between the smart grid elements. This paper studies the effect of two power converter modulation techniques: conventional fixed-frequency modulation and spread-spectrum modulation, on the performance of the Power Line Communication (PLC) signal. The paper presents a practical implementation of the system and discusses the results for different operating scenarios.

Optical wireless communications have attracted widespread attention in the traditional power industry because of the advantages of large spectrum resources, strong confidentiality, and freedom from traditional electromagnetic interference. This paper mainly summarizes the major classification and frontier development of power industry optical wireless technologies, including the indoor and outdoor channel characteristics of power industry optical wireless communication system, modulation scheme, the performance of hybrid power line, and indoor wireless optical communications system. Furthermore, this article compares domestic and foreign experiments, analyzes parameters for instance transmission rate, and reviews different application scenarios such as power wireless optical positioning and monitoring. In addition, in view of the shortcomings of traditional power technology, optical wireless power transfer technology is proposed and combined with unmanned aerial vehicles to achieve remote communication. At last, the main challenges and possible solutions faced by power industry wireless optical technologies are proposed.

Power line communications (PLC) is a known low cost technology which is easily installed and extended to the various connections especially to areas with poor wireless coverage. Unfortunately, designers and users experience technical problems that arise from the difficulty of operating on a complex time varying medium and that limits the expected high throughput. Therefore, testing and understanding network dynamics of PLC systems before usage is a necessity. This paper presents the findings obtained from the experiments carried out in order to verify the throughput performance of PLC systems. Experimental measurements are realized in different testbeds, under different times and conditions, in order to achieve an idea of the practical PLC performance. Data obtained from the measurements have been stored and the throughput is analyzed by the help of software. Following, using distribution fitting methods, it is shown that the PLC throughput may be modeled by the extreme value distribution. Furthermore, adding a basic noise to the network, simply by lamps, results with a degraded performance. The noise changes the parameters of the derived distributions; a decrease in expected value and an increase in standard deviation are observed.

A great deal of attention has been recently given to Machine Learning (ML) techniques in many different application fields. This paper provides a vision of what ML can do in Power Line Communications (PLC). We firstly and briefly describe classical formulations of ML, and distinguish deterministic from statistical learning models with relevance to communications. We then discuss ML applications in PLC for each layer, namely, for characterization and modeling, for the development of physical layer algorithms, for media access control and networking. Finally, other applications of PLC that can benefit from the usage of ML, as grid diagnostics, are analyzed. Illustrative numerical examples are reported to serve the purpose of validating the ideas and motivate future research endeavors in this stimulating signal/data processing field., Comment: Accepted for publication in IEEE Access. 19 pages, 15 figures, 142 references. Added Sec. II-C

Power line communications (PLC) have been an active research area for many years and it is still the case, mainly because they present economic and technical natural advantages for a wide range of applications using the existing electrical grid as transmission medium. In this paper, the authors provide an update on PLC technologies and their applications in Smart Grids, the main challenges they are currently facing, how they can be addressed, and the current research initiatives.

AMIs (Advanced Metering Infrastructures) present an important role in Smart City environments, especially from the point of view of distribution and customers, offering control and monitoring capabilities. The use of PLC (Power Line Communication) technology offers a wide range of advantages in AMI, including not needing to deploy an additional communication infrastructure. However, the electrical network was not initially designed for communications, as these networks pose problems depending on the connected loads, such as network impedance variation, frequency selectivity or noise. For this reason, the use of simulators is proposed to facilitate the deployments based on PLC networks, and analysis and diagnosis tools for the identification of problems in operating networks are also required. This paper presents a toolkit for evaluating and analyzing the performance of PLC networks. This toolkit is composed of SimPRIME, a simulator for the evaluation of NB-PLC PRIME (PoweR line Intelligent Metering Evolution) networks’ performance, SimBPL, a simulator for the evaluation of MV-BPL (Broadband Power Line over Medium Voltage) cells’ performance, and PRIME Analytics, a forensics tool that allows diagnosis of communication problems in PRIME operational networks based on traffic traces. The toolkit has been developed throughout several research projects in close collaboration with DSOs (Distribution System Operators) and equipment manufacturers, so they provide solutions to actual problems of these industry key players and have been adapted to facilitate their use. As a result, the tools are accessible through web applications to increase their usability, portability, and scalability. These applications represent the first steps in offering PLC simulation and analysis as a service that could benefit the research community, academia, and industry.

In this contribution, the authors perform the design and show the experimental results relative to a prototype of a combined wireless power transfer (WPT)–power line communications (PLC) system, in which the WPT channel is interfaced to a PLC environment to allow data transfer when the cabled connection is no longer available. The main rationale behind this idea stays in the fact that PLC communication is now a popular choice to enable communications, for instance, in smart grids and in home automation, while WPT devices start to be available in the market (i.e. for mobile phones) and soon they will be a reality also for higher power (i.e. vehicle battery charging). In particular, theoretical insights about the requirements of the system are given; a two coils system has been implemented and a measurement campaign, together with simulations, show that the system is of great potentiality and could be used in applications where both wireless power and data transfer are needed (such as vehicles battery charging), achieving maximum power transfer and good data rate in order to transmit high-speed signals.

International audience; Today an increasing number of batteries areequipped with a digital Battery Management System (BMS)either for safety issues, lifetime improvement, or both. In order toavoid the use of dedicated wiring for communicating with theseBMS, a Power Line Communication (PLC) solution is proposedto communicate through the DC power line inherent in thesesystems. This solution is also designed to be directly compatiblewith the existing Controller Area Network (CAN) controllersintegrated in a large number of commercially availablemicrocontrollers. It uses a single carrier generator in order togenerate a shared carrier signal on the bus. Each modem canmodulate this common carrier signal by switching the impedanceit presents on the bus. In a first part, this paper proposes anoverview of the industrial context of this PLC solution, includingsimulation results and discussion of the theoretical limits of thesystem. Then, the digitization stage interfacing the controller tothe power line is described and a first prototype is validatedthrough discussion of experimental results obtained within anactual industrial environment.

This paper proposes a synthetic statistical top-down MIMO power line communications channel model based on a pure phenomenological approach. The basic idea consists of directly synthesizing the experimental channel statistical properties to obtain an extremely compact model that requires a small set of parameters. The model is derived from the analysis of the in-home 2 $\times$ 3 MIMO PLC channel data set obtained by the ETSI Specialist Task Force 410 measurement campaign in the band 1.8-100 MHz. The challenge of modeling the channel statistical correlation, exhibited among the frequencies and between the MIMO modes, in compact form is tackled and it is shown that a small set of parameters can be used to reconstruct such a correlation behavior. The model is validated and compared to the measured channels, showing a good agreement in terms of average channel gain, root-mean-square delay spread, coherence bandwidth, and channel capacity distribution., Comment: A version of this paper has been accepted for publication to IEEE Transactions on Communications - \copyright\ IEEE 2017. The paper consists of 11 pages, 8 figures, 4 tables

Power line communication (PLC) has enabled manysmart grid applications and functionalities over the past few years.Secure communications over such links however remains a crucialaspect for further development. Due to their shared nature, akinto wireless, PLC channels can benefit from many wireless-typesecurity techniques, including physical layer security. To this end,and in contrast to existing studies which focus on non-cooperativePLC systems, this paper considers the application of physical layersecurity in cooperative PLC networks in the presence of passiveeavesdropping. We analyze the performance of such systems usinglog-normal correlated channel models taking into account backgroundand impulsive noise components. Furthermore, the impactof PLC/wireless coding diversity on the system secrecy capacity isevaluated. The results include accurate mathematical expressions forproviding an insight into the secrecy capacity and outage probabilityperformance of such systems under various network scenarios.

Leakage of information in power line communication (PLC) networks is a threat to privacy and security. A way to enhance security is to encode the transmitted information with the use of a secret key. If the communication channel exhibits common characteristics at both ends and these are unknown to a potential eavesdropper, then it is possible to locally generate a common secret key at the two communication ends without the need for sharing it through the broadcast channel. This is known as physical layer key generation. To this aim, known techniques have been developed exploiting the transfer function of symmetric channels. However, the PLC channel is in general not symmetric, but just reciprocal. Therefore, in this paper, we first analyze the characteristics of the channel to verify whether physical layer key generation can be implemented. Then, we propose two novel methods that exploit the reciprocity of the PLC channel to generate common information by the two intended users. This information is processed through different quantization techniques to generate secret keys locally. To assess the security of the generated keys, we analyze the spatial correlation of PLC channels. This allows verifying whether the eavesdropper&rsquo, s channels are weakly correlated with the intended users&rsquo, channel. Consequently, it is found that the information leaked to a possible eavesdropper has very low correlation to the locally generated key. The analysis and proposed methods are validated on a measurement dataset.

Smart meters (SMs) are key components of the smart grid (SG) which gather electricity usage data from residences and businesses. Home area networks (HANs) are used to support two-way communications between SMs and devices within a building such as appliances. This can be implemented using power line communications (PLCs) via home wiring topologies. In this paper, a bottom-up approach is designed and a HAN-PLC channel model is obtained for a split-phase power system which includes branch circuits, an electric panel with circuit breakers and bars, a secondary transformer and the wiring of neighboring residences. A cell division (CD) method is proposed to construct the channel model. Furthermore, arc fault circuit interrupter (AFCI) and ground fault circuit interrupter (GFCI) circuit breaker models are developed. Several HAN-PLC channels are presented and compared with those obtained using existing models.

This paper is focused on the possibility of employing narrow band power line communication (PLC) in medium voltage (MV) distribution networks. The topic is investigated by means of both simulations and experimental tests, which were carried out in the distribution network of Ustica Island. In detail, a two-way MV communication was tested between two secondary substations connected by an MV cable power line. Each substation has a by-pass connection at MV bus-bars and an MV/LV oil filled power transformer. In this paper, the MV and the PLC systems under test are described and the experimental tests are presented, which were carried out to evaluate the parameters of the simulation model. The aforesaid model is described and a comparison is shown between simulation and results of experiments, which were carried out in the presence of voltage net, i.e., 24 kV. Finally, the possibility is investigated of a reliable communication and the faster achievable bit-rate; the analysis is performed by means of further experimental results of several communication tests, which were carried out with different modulation techniques.

International audience; Power Line Communication (PLC) has emerged in recent years as an attractive communication technique. The main advantage of this technology is its ability to benefit from the existing electrical network infrastructure for the transmission of electromagnetic signals. However, electrical wires were not initially designed to propagate communication signals at frequencies above 1 kHz. As a consequence, the communication channel between the transmitter (Tx) and the receiver (Rx) is a difficult channel, generating attenuation and multiple propagation paths. This chapter focuses on one of the main limitations related to the PLC technology, namely, the generation of unintentional radiated signal. This phenomenon is mainly due to the unbalanced nature of the electrical network. The variation of the impedances of the loads connected to the network as well as the unequal length of the live and neutral wires (due to single-phase switches) converts the differential PLC signal into common-mode current flowing through the network. Consequently, the copper wires used for transmitting the useful signal act as an antenna, and part of the transmitted power is radiated. This not only results in stronger signal attenuation at the Rx but also leads to electromagnetic compatibility issues, as the radiated signal may interfere with other existing services, such as amateur radio or short-wave broadcasting. The presented approach tries to simultaneously reach two complementary goals by means of digital signal processing. The first intention is to focus the transmitted signal at the Rx location. The power gain linked to this energy focalisation allows in turn relaxing the required power level at the Tx, hence generating less electromagnetic interference. A second target is to reduce the level of energy dissipated at any location except the intended Rx. In particular, it is desirable to minimise the level of radiated power from the electrical wires. These two benefits already appear as features of a known technique in the field of wireless transmission: time reversal. This chapter presents an experimental analysis of time reversal as a means to mitigate radiation effects for wired signal transmission.

It has been demonstrated that Power Line Communications (PLC) can interfere with some radio services. In order to avoid it, PLC standards specify not to transmit at the same frequencies where these radio services operate. These frequencies are called the masked tones. As they carry no transmitted power, the masked tones can be used to detect and cancel impulsive noise (IN), which most of times is wideband and leaks out into the whole PLC band. This research work presents a new procedure to identify and eliminate IN from PLC receivers, being able to recover the original signal samples which have been impaired by the IN pulses.

In this contribution, the authors evaluate the possibility of using separated access points for power and data transfer in a coupled Wireless Power Transfer-Powerline Communication system. Such a system has been previously proposed by the authors for specific applications, in which Wireless Power Transfer (WPT) should take place in a system where data are transmitted over the power grid. In previous works the authors have performed lab tests on a two coils WPT system equipped with a set of filters to also allow an efficient data transfer. When a multiple coil WPT system is chosen, additional possibilities arise: the access point for power and data can be differentiated, with the aim of maintaining the designed power efficiency and increase data transfer capacity. In this study a four coils WPT system is thoroughly analyzed, modelled, implemented and measured, and a set of guidelines for the correct design (in terms of performance optimization) of the data transfer is given.

Narrowband Power Line Communications (NB-PLCs) are investigated as an alternative option for transferring low rate smart grid (SG) data via Medium Voltage (MV) power lines. In this framework, two variants of orthogonal frequency division multiplexing are examined, namely Filtered-OFDM (F-OFDM) and Wavelet-OFDM (W-OFDM), in an attempt to determine which of them is capable of transmitting low rate SG data to greater distances over non-branched MV power lines. The reach of NB-PLC signals via MV power lines is estimated, taking into account the transfer function of the relevant PLC channels and noise mechanisms as well as the specific features of the two modulation options under consideration. Simulations show that NB-PLC transmission constitutes a technically feasible and economically affordable option for exchanging low rate data with remote SG nodes dispersed over the MV grid. Moreover, simulations show that F-OFDM allows low rate data transmission to considerably greater distances compared to W-OFDM.

ITU-T G.9904 standard, also known as PoweRline Intelligent Metering Evolution (PRIME), is a Power Line Communications standard for advanced metering, grid control and asset monitoring defined by the International Telecommunication Union (ITU). In this paper, an analysis about how different characteristics of the communication channel and types of noise might affect the system performance is carried out. This study is based on simulations of the PRIME physical layer using different channel characteristics and transmission parameters. The conclusions obtained are very valuable for better understanding the behavior of the ITU-T G.9904 (PRIME) standard in the field, allowing future improvements in deployment strategies and equipment design. This work has been partially supported by the Spanish Ministry of Economy and Competitiveness (project TEC2015-67868-C3-1-R), the Basque Government (project IT 683-13) and the University of the Basque Country (UPV/EHU) within the program for the specialization of the postdoctoral researcher staff.

This paper assesses the performance of actual PRIME v1.3.6 and PRIME v1.4 systems when used for Smart Metering applications. The analysis is performed at the application level using the DLMS/COSEM stack. Hence, it considers performance indicators that are of practical interest for distribution system operators, such as the availability and the average time needed to read the energy load profile of all the meters. To this end, two test networks with 112 smart meters have been deployed in the laboratory (to ensure the stability of the network). In one of them all the Service Nodes communicate directly with the Base Node, while there exist up to 5 switching levels in the other tested network. First, the PRIME v1.3.6 system is evaluated, stressing the significant performance gain that can be obtained by implementing some MAC layer strategies, which are compatible with the specification but not specifically defined on it. Then,the improvement offered by the PRIME v1.4 system is assessed. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

This contribution briefly shows the main characteristics of a system that combines power and data transfer in a single device; in particular, the Wireless Power Transfer channel is used also as data transfer when it is embedded into a Power Line Communication environment. This is achieved by the use of specifically designed filters and has the main advantage of retaining the data transfer capability (of a PLC system) when the cabled connection is no longer available.

International audience; Despite being a well-established ingredient to many wireless systems, multiple input multiple output (MIMO) signal processing has only recently been considered for broadband power line communications (PLC). Adapting multiple-antenna transmission and reception techniques to a wired medium such as the electrical grid requires solving a number of issues, both regarding the physics of electromagnetic transmission and the optimization of the signal processing strategies. In the last few years, significant steps were made to demonstrate the benefits of MIMO PLC and to develop the necessary hardware. As a result, MIMO PLC has been adopted in several broadband PLC specifications, precisely as part of ITU-T G.hn in Recommendation G.9963, and as part of the industry specification HomePlug AV2, which is backward compatible to IEEE 1901. This article reviews important aspects of MIMO PLC, highlighting its similarities and main differences with classical wireless MIMO. It focuses first on the peculiarities of the electrical grid, with a survey of PLC channel and noise characterization in a MIMO context. It further estimates MIMO PLC channel capacity adhering to the electromagnetic compatibility regulations currently in force. Besides, MIMO signal processing techniques most suited to PLC environments are discussed, allowing for throughput predictions. It is found that eigenbeamforming is the best choice for MIMO PLC: the full spatial diversity gain is achieved for highly attenuated channels and maximum multiplexing gain is achieved for channels with low attenuation by utilizing all spatial streams. It is shown that upgrading from a conventional single input single output (SISO) PLC configuration to a 2 by 2 MIMO configuration the throughput can be more than doubled while coverage is increased. The survey concludes with a review of specific MIMO PLC system implementations in the specifications ITU-T G.9963 and HomePlug AV2.

International audience; In this paper a simulations-based evaluation of the energy efficiency performance of relay Power Line Communication (PLC) networks is reported. Our system model is based on two PLC modems as source/destination and one relay modem with time division Decode-and-Forward (DF) scheme. In addition to the transmission power, we consider the static power of PLC modems in our energy consumption model and find the best energy efficiency performance for DF strategy by optimizing the transmission time of each link. Through extensive numerical results and two representative scenarios, we show that the use of PLC relaying with optimal time allocation allows for better performance than direct transmission, yet achieving the same rate of the direct transmission.

WOS: 000358810300008, In this study, a channel model which is based on practical channel measurements obtained from electrical networks in Turkey is proposed for power line communication (PLC) systems. Experimental measurements are realized in different cities and various indoor places such as laboratory, university office and apartment house in order to achieve a general and appropriate PLC channel model for different locations and environments. Acquired data from the electric grid are stored on a database and PLC channel modelling process is carried out depending on these data through curve fitting methods. Moreover, parameters of the derived mathematical model are optimized by using artificial bee colony algorithm. Results show that the PLC channel model proposed in this study can be utilized to simulate PLC systems and to perform conformance tests of prototypes. (C) 2015 Elsevier B.V. All rights reserved., Scientific and Technological Research Council of Turkey (TUBITAK) [113E425], This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under grant 113E425.

International audience; Power Line Communications (PLC) are commonly used in the indoor environment to set up a broadband network while using the existing electrical infrastructure. However, asymmetries in the electrical network are responsible for the conversion of the differential mode injected current into common mode current, which in turn generates undesired electromagnetic (EM) radiation. This paper presents a parametric study of the EM emissions due to indoor PLC, on the basis of Finite Difference Time Domain (FDTD) simulations and using a realistic coupler model. Results show the influence of the different parts of the electrical network and of the building structure on the radiated field.

This work deals with the characterization of a power line, devoted to energy distribution and supplied by DC voltage, aiming to use the same line for exchange of information by means of a Power Line Communications (PLC) system. For this purpose, the DC power grid has been considered as a transmission line. The characteristic parameters have been obtained by the short-circuit and open-circuit impedance measurements. Then, the propagation constant and characteristic impedance curve vs. frequency have been calculated. Finally a model of the transmission line has been implemented in Matlab/Simulink® environment and the time domain response of the loaded network has been achieved. Experimental results confirming the validity of the proposed approach and the limitations of the model are given at the end. © 2014 IEEE.

International audience; The idea of using power lines also for communication purposes has already been around at the beginning of the last century. It is now broadly referred to as power line communications (PLCs). The obvious advantage is the widespread availability of electrical infrastructure, so that theoretically, deployment costs are confined to connecting modems to the existing electrical grid. Power line technologies can be grouped into the following: ultra narrowband (UNB) technologies operating at very low data rate in the ULF band (0.3-3 kHz) or in the upper part of the SLF (30-300 Hz) ; narrowband (NB) technologies operating in the VLF, the LF and in parts of the MF bands (3-500 kHz), and capable of data rates ranging between a few kbit/s and around 500 kbit/s ; and broadband (BB) technologies operating in the MF, HF or VHF bands (1.8-250 MHz) and presenting a PHY rate ranging from several Mbit/s to several hundred Mbit/s. This chapter provides an overview of current NB-PLC and BB-PLC systems.

International audience; Multiple input multiple output (MIMO) systems have been used for many years in the field of wireless communications. The huge increase in coverage and capacity offered by MIMO technology are the key benefits of using multiple sensors at the transmitter and receiver . Recently, MIMO technology has been applied in the context of power line communications (PLCs), with the aim of offering higher channel capacity and therefore larger system coverage, by including the use of the protective earth (PE) wire in addition to the line (L) and neutral (N) wires. SNR values observed in typical PLC scenarios can be much higher than in the case of a classical wireless communication. This high SNR condition is beneficial for MIMO transmission, as it ensures a high capacity gain with respect to single input single output (SISO) transmission, even if the channel presents a high degree of spatial correlation. This chapter is divided into two main sections. First, the PLC channel capacity offered by MIMO technology is analysed in details. The channel capacity provides an upper limit for achievable throughput and does not take system implementation or a particular MIMO scheme into consideration. The achievable throughput for different MIMO schemes in an OFDM system with adaptive modulation is then investigated.

International audience; In January 2012, the HomePlug Alliance published the HomePlug AV2 specification. HomePlug AV2 enables gigabit-class connection speeds by leveraging the existing power line wires while remaining fully interoperable with other technologies for in-home connectivity, such as HomePlug AV, HomePlug Green PHY and IEEE 1901. In this chapter, we highlight the key differentiating HomePlug AV2 features as compared with the HomePlug AV technology. At the PHY layer, HomePlug AV2 includes the following: multiple-input-multiple-output (MIMO) signalling with beamforming ; extended frequency band up to 86 MHz ; efficient notching and power back-off to meet EMC regulations ; and EMC-friendly power boost to optimize the transmit power. At the MAC layer, HomePlug AV2 includes the following: power save mode to improve energy efficiency ; short delimiter and delayed acknowledgements to increase the overall transmission efficiency ; and immediate repeating to expand the coverage. All these features improve the quality of service of HomePlug AV2 power line modems by improving coverage and robustness of communication links. The chapter sections provide technical details for all the previously mentioned features. The chapter begins with a brief overview of HomePlug AV technology and a presentation of the overall HomePlug AV2 system architecture. Next sections detail the new PHY and MAC layers. Finally, the performance gain of HomePlug AV2 over HomePlug AV is summarized.

International audience; In the last decade, there has been an emergent attention in the utilization of existing power distribution lines for broadband power line communications (BPLC). PLC technology is becoming more widely adopted because of its excellent fit with smart grid and in-home network applications, with no infrastructure cost. However, PLC not only has a limited spectrum (< 30MHz) and limited coverage (< 1 mile) due to power line cable attenuation but also has some time-varying channel impairments, including multipath fading and RF noise. We investigate a quasi-stationary OFDMA-based BPLC local area network (LAN) for the smart home network or small-scale smart grid (also termed micro-grid) services over indoor power lines, where every nodes are assumed to be equipped an impedance matching circuit (IMC); then, since plug-in or switchoff of nodes do not change the network topology anymore, link budgets of the overall BPLC network are easily estimated even with some channel variations (RF noise, etc) and so its resource management with reliability and flexibility is possible. In this paper, we focus on the cluster-based medium access control (MAC) layer design and resource management of the two types of OFDMA-based BPLC LANs: centralized (AP-based) LAN and distributed (ad-hoc based) LAN.

The problem tackled is selecting a viable method for communication among pumps in a district heating system. This system is viewed as a metropolitan wireless sensor network, the nodes of which are confined underground and physically connected by pipes. In a further horizon, providing sophisticated control systems for similar urban utilities motivates this research problem. Here we have reported the results of investigating several potential methods for realizing the idea of “the talking pumps” in a district heating system. This includes a diverse list of key references, simulations for some methods and experimental results for some others, followed by selection of the most appropriate option. The methods considered used (1) acoustic waves through water and pipelines; (2) power-line communications; (3) the electrical conductivity of pipes; (4) cell-phone infrastructure; (5) free and guided radio-frequency (RF) electromagnetic (EM) waves; and (5) free and guided very low frequency (VLF) electric and magnetic fields, also known as magnetic induction. The viability of the latter method was verified by simulations and primitive experimental results.

International audience; In the recent years, the Multiple-Input Multiple-Output (MIMO) techniques have emerged as an important research field for enhancing the throughput of in-home Power Line Communication (PLC) systems by exploiting the additional Protective Earth wire. The development of such systems requires an accurate description of the noise in the propagation channel. This paper presents two statistical models for the background noise found in MIMO PLC channels, based on noise measurements performed in five houses. In the proposed models, the spectral characteristics of MIMO background noise are presented, in 2-150 MHz range, following two existing formalisms for Single-Input Single-Output SISO) PLC noise.

Power Line Communication (PLC) systems are currently envisioned as a possible solution for distributing multimedia contents and allowing Internet access with a capillary (already built) network without demanding further infrastructure. The real challenge for PLCs consists in providing connectivity where Public Switch Telephone Network (PSTN)-based Internet Access and/or Wi-Fi/WiMAX seem to be unable to solve the problem of Digital Divide. In this paper we introduce a new metric, i.e. the goodput, to balance transmission rate and bit error rate (BER) in resource allocation issues for Power Line Communication systems. In detail, we state the well-known integer bit-loading problem as a goodput maximization with constraints on the power consumption and the maximum decoding time. The use of Trellis Coded Modulation (TCM) allows to pursue the goodput maximization weighing error probability and transmission rate which would have otherwise been in trade-off. Numerical results are presented to stress how our solution improves system performances, both in ideal conditions and with additional impairments such as crosstalk and impulsive noise, with respect to the conventional Maximum Rate (MR) and Minimum BER (MB) approaches and to validate the suitability of TCMs in comparison with higher complexity codes.

Power Line Communications (PLCs) enable new and highly convenient networking functions in the framework of Smart-Grids and use an already built-in network. A Multiple Input Multiple Output (MIMO) architecture can strongly improve the PLC performances and links' reliability. In this contribution the effect of self-interference generated by relay nodes has been considered and the MIMO potentials for spatial multiplexing and interference suppression have been taken into account. The importance of channel knowledge has been also considered from a numerical result point of view in order to give some instruments for network planning.

In a multiuser scenario, the bit-loading, which has proven decisive in resource optimization for Power Line Communications (PLCs), has to be coupled with channel assignment to fully exploit its potential. Unfortunately, finding the most performing combination of channel and power allocation leads to integer (or mixed) programming problems, which are known to be NP-hard. To overcome the complexity of the resulting optimization problem, in this paper we propose an iterative solution that is able to guarantee both fairness and Quality of Service (QoS) to the users when the overall power consumption of the system is bounded and each subchannel emission is limited. This solution embeds a Connection Admission Control (CAC) that allows to leave out badly-connected users that otherwise would negatively affect the comprehensive system performance. Numerical results compare the presented resource allocation with the common greedy-based single user approach.

International audience; In this paper, we propose an original method for analyzing the performance of comb-type pilot-aided channel estimation for power line communications. Our method is based on a unified mathematical decomposition of the channel estimation error, which takes both the signal-to-noise ratio of the pilot sub-carrier locations and the interpolation kernel used into account. We demonstrate that the channel estimation error is composed of two terms that evolve differently according to the pilot spacing and the interpolation technique used. The error due to additive noise over channel transmission is formulated by a simple easily used analytic expression. Our results for some practical situations show that good performances can be achieved with a simple linear interpolation

Low voltage electrical power distribution networks represent an attractive medium for digital communications. A modified frequency hopping spread spectrum modulation scheme has been reported as an efficient method to overcome high interference level and time-variant and frequency-selective attenuation on power lines. In spread spectrum systems, the cost-effective solution of synchronisation problem is of decisive importance. Fluctuations of power line frequency, asymmetrical loading on three-phase networks and propagation delay along the cable, limit the data rate and seriously degrade performance of the systems which use zero crossings of the mains voltage as a synchronisation reference. In this paper we propose a digital receiver that derives timing information from the received signal, and therefore, it is not sensitive to the mentioned effects. The receiver design is based on sliding DFT calculation. To overcome time-variant attenuation, an adaptive algorithm is used.

Power Line Communications (PLC) is a technology that takes advantage of the existing electrical infrastructure to deploy communication networks. This paper proposes an architecture for the physical layer (PHY) of a PLC transceiver based on Orthogonal Frequency Division Multiplexing (OFDM) and inspired in the IEEE 1901 standard for Broadband PLC. The designed system is synthesized on a Xilinx Spartan-6 FPGA device, and supports data rates up to 107 Mbps.