Are Power Line Communications (PLC) a good candidate for Smart Grid applications? The objective of this paper is to address this important question. To do so, we provide an overview of what PLC can deliver today by surveying its history and describing the most recent technological advances in the area. We then address Smart Grid applications as instances of sensor networking and network control problems and discuss the main conclusions one can draw from the literature on these subjects. The application scenario of PLC within the Smart Grid is then analyzed in detail. Because a necessary ingredient of network planning is modeling, we also discuss two aspects of engineering modeling that relate to our question. The first aspect is modeling the PLC channel through fading models. The second aspect we review is the Smart Grid control and traffic modeling problem which allows us to achieve a better understanding of the communications requirements. Finally, this paper reports recent studies on the electrical and topological properties of a sample power distribution network. Power grid topological studies are very important for PLC networking as the power grid is not only the information source but also the information delivery system-a unique feature when PLC is used for the Smart Grid.

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For the Grid and Through the Grid: The Role of Power Line Communications in the Smart Grid

一种高速调制解调器，它通过电话线发送和接收一载频集的数字数据。 该调制解调器包括在载波之间可变地分配数据和功率，以便补偿等效噪声和使数据速率最大的系统。 此外，也介绍不需要一个均衡网络、可自适应地分配信道的控制和可跟踪线上参数变化的系统。

Ensemble modem structure for imperfect transmission media

We propose an efficient bottom-up power-line communication (PLC) channel simulator that exploits transmission-line theory concepts and that is able to generate statistically representative in-home channels. We first derive from norms and practices a statistical model of European in-home topologies. The model describes how outlets are arranged in a topology and are interconnected via intermediate nodes referred to as derivation boxes. Then, we present an efficient method to compute the channel transfer function between any pair of outlets belonging to a topology realization. The method is based on a systematic remapping technique that leads to the subdivision of the network in elementary units, and on an efficient way to compute the unit transfer function referred to as the voltage ratio approach. The difference from the more conventional and complex ABCD matrix approach is also discussed. We finally show that the simulator can be configured with a small set of parameters and that it offers a theoretical framework to study the statistical PLC channel properties as a function of the topology characteristics, which is discussed in Part II of this work.

Bottom-Up Statistical PLC Channel Modeling—Part I: Random Topology Model and Efficient Transfer Function Computation

A method for communicating among nodes in a network includes determining, by a transmitter, a first frequency band and at least a second frequency band to be used for communicating data packets, wherein a maximum allowable power spectral density in the first frequency band is greater than a maximum allowable power spectral density in the second frequency band The method also includes adjusting power spectral density for a first group of frequencies in the first frequency band such that the adjusted power spectral density of the first group does not exceed the maximum allowable power spectral density of the first frequency band and a quantization noise introduced by the transmitter is less than a threshold value for a signal transmitted in the second frequency band The method further includes modulating at least a portion of a data packet transmitted by the transmitter to at least a first receiver in accordance with the adjusted power spectral density

Transmit power control

Advanced communication technologies have allowed the power-line-communication (PLC) channel to be a transmission medium that enables the transfer of high-speed digital data over the classical indoor electrical wires. The development of PLC systems for Internet, voice, and data services requires measurement-based models of the transfer characteristics of the mains network suitable for performance analysis by simulation. This paper presents a deterministic model describing the magnitude and phase of complex transfer functions of power-line networks using only one parameter. First, a PLC channel classification is realized, and an average magnitude and phase channel model by class is proposed. Second, the multipath characteristic of PLC channels is introduced. A statistical-based channel magnitude generator is built, and a group delay-based phase model is suggested.

Indoor Power-Line Communications Channel Characterization Up to 100 MHz—Part I: One-Parameter Deterministic Model

Estimations of coherence bandwidth and time-delay parameters from wideband channel sounding measurements made in the 30 kHz-100 MHz band in several indoor environments are described in and taken back in this paper. Powerline communications (PLC) modems rather see a channel which starts almost from 2 MHz . A comparison between coherence bandwidth and time-delay parameters estimated in both frequency bands 30 kHz-100 MHz and 2 MHz-100 MHz is elaborated in this paper. Results are intended for applications in high-capacity indoor power-line networks. The investigation is aimed to show that the PLC channel studies in a band starting from a frequency lower than 2 MHz distorts the real values that an implementer should take, as the PLC modem see only the frequencies from 2 MHz. The coherence bandwidth and the time delay parameters are estimated from measurements of the complex transfer functions of the PLC channels. For the 30 kHz-100 MHz frequency band, the 90 th percentile of the estimated coherence bandwidth at 0.9 correlation level stay above 65.5 kHz and below 691.5 kHz. It was observed to have a minimum value of 32.5 kHz. The maximum excess delay spread results show that 80% of the channels exhibit values between 0.6 s and 6.45 s. And a mean rms delay spread of 0.413 s is obtained. The passage to the 2 MHz-100 MHz frequency band induced an increase of the coherence bandwidth, whose min value is brought back to 43.5 kHz, and an important reduction of the time delay parameters: The min, max, mean, and standard deviation values of the maximum excess delay are almost divided by 2. For the twice frequency bands, this paper studies, also, the variability of the coherence bandwidth and time-delay spread parameters with the channel class , and thus with the location of the receiver with respect to the transmitter, and finally relates the rms delay spread to the coherence bandwidth.

Indoor Power-Line Communications Channel Characterization up to 100 MHz—Part II: Time-Frequency Analysis

Power Line Communications (PLC) is used for information exchange over the lines installed for delivering the electrical power. Inhome PLC is a technology which delivers telecom services to every corner of a household through already existing electrical wiring. In recent years, PLC has emerged as a potential candidate for domestic high bit rate services. The current inhome PLC technology, based on Single-Input Single-Output (SISO) configuration, under achieves the capacity offered by the physical PLC channel. The inhome PLC channel offers multiple signal feed ports as, usually, it comprises of three wires: Phase, Neutral and Protective Earth. The measurements and results presented in this paper demonstrate that up to 90% enhancement in inhome PLC channel capacity is possible by using multiple-input multiple-output (MIMO) technique.

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MIMO communications for inhome PLC networks: Measurements and results up to 100 MHz

In the [1.8–30] MHz frequency band, EMC standards prohibit power line communications (PLC) to emit on the frequencies which could be used by HAM radio in order to protect them. This implies an transmit power restriction in these radio frequencies and consequently a throughput limitation. With the aim to increase the data rates, the solutions envisaged today consist in limiting the number of notched frequencies as well as in increasing the used frequency band, which can henceforth overlap with the FM band [87.5–108] MHz for future PLC systems. With the current static notching solution, the whole frequencies of the FM band can be notched during PLC transmission. As in a given environment and at a given time, only a part of the FM radio frequencies are really received, a cognitive EMC approach is proposed in this paper. The power line network is demonstrated to be a good antenna that can detect all present radio frequencies and a cognitive detection method is proposed. By means of simulations, it is also shown that the use the cognitive technique improves the data rates of the PLC systems.

Cognitive detection method of radio frequencies on power line networks

Multiple-Input Multiple-Output (MIMO) techniques have recently become an important research field for enhancing the performance 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 propagation channel. This paper presents a statistical model for the MIMO PLC channel, based on an extensive set of MIMO channel measurements performed in five houses. In this model, the Phase-Neutral link is described as a multipath channel with frequency variable attenuation, following a formalism first proposed by Zimmermann and extended statistically by Tonello. The full channel matrix is obtained by suitably modifying the path phase. The resulting channel matches our experimental measurements, and reproduces the correlation observed in the measured MIMO channel matrix.

Ahmed Zeddam

Papers

Indoor Power-Line Communications Channel Characterization Up to 100 MHz—Part I: One-Parameter Deterministic Model

Indoor Power-Line Communications Channel Characterization up to 100 MHz—Part II: Time-Frequency Analysis

MIMO communications for inhome PLC networks: Measurements and results up to 100 MHz

Cognitive detection method of radio frequencies on power line networks

A Channel Model for Multiple Input Multiple Output in-home Power Line Networks