Power Line Communication Environment Research Articles

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

This paper presents Discrete Wavelet Transformed Sparse Code Multiple Access (DWT-SCMA) in Power Line Communication (PLC) systems. In the present internet of things era, PLC provides an established infrastructure for low-cost and reliable indoor connectivity. PLC systems can benefit from the Sparse Code Multiple Access (SCMA) technique, which allows multiple users to access a frequency slot simultaneously to maximize spectrum efficiency. However, interuser interference arises in SCMA when numerous users map their data to the same frequency resource; this, in turn, is likely to be enhanced by the noisy PLC channel. This article adopts the intriguing aspects of DWT to address the interference difficulties. A mathematical model of the proposed technique is also presented and compared with Fast Fourier Transformed SCMA (FFT-SCMA). In the PLC environment, DWT-SCMA is found to outperform FFT-SCMA.

Adaptive thresholding algorithm for detection of coded signals in narrowband powerline communication systems

ABSTRACT werline Communication (PLC) signals are affected by a combination of different sources of noise. Among them, impulse noise represents the most harmful component, making the use of encoding algorithms an essential requirement. Algorithms based on Complementary Sequences (CS) are an attractive option for signal detection in conditions of low signal-to-noise ratios (SNR). One of the main characteristics of CS is the high SNR gain by computing the sum of their autocorrelation functions, which, in a noiseless scenario, results in a Kronecker delta. In the presence of noise, the amplitude of main deltas is no longer proportional to the length of the sequences, and a variable number of random amplitude sidelobes emerge around it. This work analyses some of the algorithms present in the bibliography and proposes a novel dynamic algorithm to detect the correlation deltas immersed in the PLC impulse noise. The proposal is based on the estimation of the noise variance and the correlation peaks in order to compute a near-optimal validation threshold. The proposal is simulated and evaluated in a PLC environment with a Middleton Class A noise model, and the algorithm performance is compared in a real communication test over the electrical network of the university building.

On the simulation of the Middleton Class-A noise model for single- and multi-carrier modulation in power line communication

We propose a novel simulation approach of the Middleton Class-A model for impulsive noise generation considering symbol-wise transmission in a real Power Line Communication environment. Then, we validate the proposed approach for both single carrier binary FSK based—and multi-carrier OFDM-based communication systems. Established analytical formulations and obtained simulation results for the impulsive noise variance distribution and the communication system error probability show that in a binary FSK system, the second order of the noise variance per symbol, as well as the error floor, are closely related to the impulsive index A. The error floor decreases when A becomes large, and its asymptotic value is equal to the Bit Error Rate (BER) for an additive white Gaussian noise channel with noise variance equal to the average variance of the impulse noise. However, in an OFDM-based system, the noise variance per symbol at the output of the demodulator, as well as the error floor in the BER curves, are fixed and independent of the impulsive index A. The proposed analysis allows us to compare binary FSK and OFDM under the same theoretical noise conditions.

Effect of Non-Optimal Amplitude Frequency Response on Transmission of Power Line Communication Signals

Power line Communication (PLC) systems represent a relatively recent and rapidly evolving technology, aimed at the utilization of the electricity power lines for the transmission of data. This is due to increasing demand of low cost telecommunication, broadband and access to internet services. Power lines are inherently the most attractive medium for home networking due to its universal existence in homes, the abundance of alternating current outlets and the simplicity of the power plug. This work presented the effect of non-optimal amplitude frequency on transmission of power line communication signals by utilizing Orthogonal Frequency Division Multiplexing (OFDM) system. The simulation was carried out using MATLAB/SIMULINK with additive white Gaussian noise (AWGN) in order to obtain correct simulation performance results. Two channels of PLC were considered, the worse channel was taken into account and the channel output signal power was obtained. Bit Error Rate (BER) of Binary Phase Shift Keying (BPSK) in conjunction with multipath channel was used for a comparative performance of the studies. The results indicated that data transmission in PLC environment needed a signal to be amplified or transmitted at higher powers. The result also showed that non-optimal amplitude frequency response had no effect on transmission of the PLC signal in the frequency bands despite the low noise signal in the system. The result demonstrated that OFDM exhibited better BER performance for providing adequate transmission channel for information over a PLC system. This approach provided accurate reliability, security and robustness for better management of available energy resources to overcome the limitations of existing Power line communication technology. Keywords: Power Line Communication, Bit Error Rate, Orthogonal Frequency Division Multiplexing, Gaussian Noise, Transmission Line, Binary Phase Shift Keying DOI : 10.7176/JIEA/10-1-03 Publication date: January 31 st 2020

Development of Top-Up And Bottom –Up Techniques for Assessment of Power Line Communication Channel Model

Power Line Communication (PLC) is the transfer of data and voice signals from one communication system to another over the electric power delivery network. However, with the advent of technology, human dependency on electricity and communication has grown beyond leaps and bounds. The power transmission line channel has not been designed with wired channel requirements for broadband applications and appears as a harsh environment for the low-power high-frequency communication signals. This study therefore evaluate the performance of PLC on power grid by simulating a practical multipath power line communication channel model using top-down and bottom-up approach. The statistical multipath parameters such as path arrival time, magnitude and interval for each category were analyzed. This is done over the frequency range of 100-300 kHz. The result shows that at 100 kHz, data can be transmitted up to 350 meters without signal distortions while for 300 kHz only 50 meters can be covered. In addition, signal attenuation with a distance of 2 km is about 0.2 of the original signal at 300 kHz and less at higher frequencies. The results in the time and frequency domains indicate that data transmission in PLC environment needs signal to be amplified at higher powers. Keywords : Power Line Communication, Power Grid, Transmission Line, Multipath Parameters, Channel Modelling, Top-Down Approach, Bottom-Up Approach. DOI : 10.7176/JNSR/9-16-03 Publication date : August 31 st 2019

Design and experimental characterization of a combined WPT–PLC system

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.

Demonstrative DC Motor Control under Power Communication Network

Power line communication (PLC) has been used to transmit and receive digital data via power line in wide application. However, power lines weren’t built for data transmission originally. In practice, data transmission is commonly subjected to switching noise by the multi-path effect. The objective of this research is to establish a platform for easily tune the controller for motor control system under the PLC environment. We build up a dynamic model to simulate the power line environment for communication and propose a frequency-shift keying (FSK) technique to modulate and demodulate the signal for the purpose of network control in the disturbed feedback control loop. A modified proportional-integralderivative controller (PID controller) on positioning control a DC servo motor is proposed to against noise corruption while achieving tracking performance.

Joint terminals and relay optimization for two-way power line information exchange systems with QoS constraints

The quality-of-service (QoS) criteria (measured in terms of the minimum capacity requirement in this paper) are very important to practical indoor power line communication (PLC) applications as they greatly affect the user experience. With a two-way multicarrier relay configuration, in this paper we investigate the joint terminals and relay power optimization for the indoor broadband PLC environment, where the relay node works in the amplify-and-forward (AF) mode. As the QoS-constrained power allocation problem is highly non-convex, the globally optimal solution is computationally intractable to obtain. To overcome this challenge, we propose an alternating optimization (AO) method to decompose this problem into three convex/quasi-convex sub-problems. Simulation results demonstrate the fast convergence of the proposed algorithm under practical PLC channel conditions. Compared with the conventional bidirectional direct transmission (BDT) system, the relay-assisted two-way information exchange (R2WX) scheme can meet the same QoS requirement with less total power consumption.

PERIODIC IMPULSIVE NOISE REDUCTION IN OFDM BASED POWER LINE COMMUNICATION

Different communication technologies are used for the transmission of information such as wireless communication, satellite communication etc. Power Line Communication (PLC) is one of the technologies using existing power cables for the transmission of information. Power cables are not designed for data transmission. So the PLC environment contains different types of noise. This paper presents a novel approach for removing periodic impulsive noise from OFDM based power line communication system. The noise is detected using periodic impulsive noise detection algorithm and the noise is filtered by using adaptive notch filter. An adaptive filter using LMS algorithm is also designed to suppress periodic impulsive noise. Then compare the Bit Error Rate (BER) of PLC system without noise filtering, with noise filtering using notch filter and with noise filtering using adaptive filtering based on LMS algorithm. Results show that the received data is same as that of input data which is transmitted. Simulation results shows that PLC system after noise filtering gives better results than PLC system without noise filtering.

Physical layer security in power line communication networks: an emerging scenario, other than wireless

The authors consider the secure transmission of information over power line communication (PLC) networks. The focus is on the secrecy guaranteed at the physical layer, named physical layer security (PLS). Although PLS has been deeply investigated for the wireless case, it is not the same for the PLC environment. Thus, starting from the knowledge in the wireless context, the authors extend the results to typical PLC scenarios. In particular, the PLC channel statistics is evaluated and a performance comparison among PLC and wireless channels is performed, in terms of secrecy rate distribution. For the PLC case, the secrecy rate distribution, under a total power constraint, is evaluated for both optimal and uniform power distributions in broadband channels. To provide experimental evidence, the authors consider channel measures obtained in an in-home measurement campaign. The underlying network presents a tree topology, which introduces frequency and spatial correlation among channels, and suffers from the keyhole effect, generated by branches that depart from the same node. As shown by the numerical results, these effects can reduce the secrecy rate. Finally, the authors evaluate the secrecy rate region for the multi-user broadcast channel considering both simulated channel realisations and experimental channel measures.

Influence of the channel instability on the PLC QoS

Intensive rollout of smart grids (SG) creates a special demand on communication networks. Especially, they have to supply sufficient quality of service (QoS) to a big number of customers. Therefore the required QoS becomes more demanding (e.g., minimum throughput have to be increased) and in meantime the cost of the network installation and management should be reduced. Power line communication (PLC) becomes a challenging technology inside SGs. It uses already available power cables and therefore reduces the installation costs of the network. In particular, the usage of PLC is beneficial for power utilities, which appear to be the owners of this communication medium. Nevertheless, PLC remains an emerging technology. Achievable QoS for particular PLC network scenarios are hard to predict and still need to be studied. It is reasoned by the fact, that the PLC environment (cable structure, electrical devices, etc.) induces special effects on the informational signal propagation over the communication medium. These effects may result in considerable impairments of the PLC signal. Nevertheless, with a usage of a cognitive mechanism a big part of them can be avoided or even taken as an advantage. This paper overviews the influence of the channel instability on the PLC QoS. A data link layer (DLL) of a PLC protocol can implement a channel prediction mechanism, which is beneficial for multiple PLC applications. A short description on this mechanism is also introduced in this paper.

Impulsive noise cancelation with simplified Cauchy-based p-norm filter

This paper addresses the problem of impulsive noise cancelation in digital signal processing area. The myriad and meridian filters are the type of robust filters which are very useful in suppressing the impulsive type of noise. These filters belong to the family of the robust M-filters and are controlled with only one parameter. The common property of these filters is the way of operating. They are a running window filters outputting the sample myriad or meridian of elements in the window. The cost functions of these filters have very similar structure. Its form is always log function which contains a constant and some expression that can be replaced with the p-th power of the general Lp-norm formula. In this paper the simplified Cauchy-based p-norm filter is presented. The proposed filter operates in a wide range of impulsive noise due to the proper adjustment of p exponent of the Lp-norm. The presented filter is applied to suppress an impulsive noise in testing chirp signal and in power line communications environment. Simulations results confirm the validity of the derived method of filtering and good performance of the proposed simplified Cauchy p-norm filter.

PLC Channel: Impulsive Noise Modelling and Its Performance Evaluation Under Different Array Coding Schemes

Power-line communications (PLC) is a field that has raised a lot of research in the past years. In this paper, we introduce array codes into the PLC environment and we study the channel's performance. In particular, generalized array codes (GAC), as well as row and column array codes (RAC) are applied. We examine their performance by obtaining three different code rates from each category. Therefore, the (8, 4, 4), (12, 7, 4) and (16, 11, 4) GAC codes as well as the (9, 4, 4), (12, 6, 4), and (15, 8, 4) RAC codes are used, meaning that we obtain code rates of (1/2), (7/12), (11/16), and (4/9), (6/12), (8/15) respectively. In addition, for reasons of completeness, convolutional codes are also being applied under the same channel conditions. Moreover, we suggest a hybrid coding technique, which combines the (8, 4, 4) GAC and the (15, 8, 4) RAC code in order to meet the requirements of the PLC time-varying channel and improve its performance. Concerning the system's design, we take into consideration Zimmermann's model for the PLC channel. We apply Middleton's model for the channel's background and impulsive noise, while we also introduce a novel way of estimating the system's impulsive noise. Finally, the well-known transmission technique of orthogonal frequency-division multiplexing is used. The channel's performance is evaluated in terms of the bit-error rate for different E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> values via computer simulations.