Power Line Communication Channel Research Articles

MAC Performance Analysis for Reliable Power-Line Communication Networks with ARQ Scheme.

Power-line communication (PLC) networks have been increasingly used for constructing industrial IoT (internet of things) and home networking systems due to their low-cost installation and broad coverage feature. To guarantee the transmission reliability, ARQ (automatic repeat request) scheme is introduced into the link layer of reliable PLC networks, which allows the retransmission of a data frame several times so that it has a higher probability to be correctly received. However, current studies of performance analysis for PLC MAC (medium access control) protocol (i.e., IEEE 1901) do not take into account of the impact of ARQ scheme. To resolve this problem, we propose an analytical model to investigate the MAC performance of IEEE 1901 protocol for reliable PLC networks with ARQ scheme. In the modeling process, we first establish a PLC channel model to reflect the impacts of PLC channel types (containing Rayleigh fading and Log-normal fading), additive non-Gaussian noise feature and ARQ scheme on data transmission at link layer. Next, we employ Renewal theory and Queueing dynamics to capture the transmission attempt behavior of executing IEEE 1901 protocol in the unsaturated environment with finite transit buffer size. On the basis of combining these two models, we derive the closed-form expressions of 1901 MAC metrics considering the influence of the ARQ scheme. Furthermore, we prove that the proposed analytical model has the convergence property. Finally, we evaluate the MAC performance of 1901 protocol for reliable PLC networks with ARQ scheme and verify the proposed analytical model.

Optimization algorithms for improving the performance of permutation trellis codes

In this paper, soft-decision (SD) decoders of permutation trellis code (PTC) with M-ary frequency shift keying are designed using three optimization algorithms and presented in four decoding schemes. In a concatenated code such as PTC, the Viterbi decoder for the outer convolutional code provides maximum likelihood decoding. Hence, the error correction performance is dependent on the decoding scheme used for the inner code. Due to the structure of the encoder with the modulation scheme, the channel output can be interpreted as an assignment problem. SD decoding can then be designed accordingly, using the presented, low-complexity optimization-based schemes. The bit error rate (BER) performance of the schemes are simulated in an additive white Gaussian noise (AWGN) and powerline communication (PLC) channel. The complexities of the schemes are also presented. The performance of the SD schemes are compared with the existing SD threshold detector, with BER results showing significant coding gain for certain codebooks. From the results, a reasonable trade-off between the complexity and coding gain is observed for a noisy channel such as the PLC channel.

BER performance analysis of OFDM‐based integrated PLC and MIMO‐VLC system

In the present paper, the bit error rate (BER) performance of hybrid power line communication (PLC) and multiple-input multiple-output (MIMO) visible light communication (VLC) system (HPMV) has been investigated using line-of-sight (LOS) and LOS plus first reflection (L-R1) signals for room size of 5 m × 5 m × 3 m (configuration A) and 7.5 m × 7.5 m × 3.5 m (configuration B). In the work, Rayleigh fading and Barry channel models have been considered for PLC and VLC channels respectively. The BER has been analysed by varying separations between LEDs as 0.2 m, 0.6m and 1m for both configurations. The results show that the BER for LOS and L-R1 signals decreases upto optimal separation of 0.6 m for configuration A. However, the result indicates that the required optimal separation for configuration B is more than configuration A. The channel frequency response of MIMO-VLC and HPMV system has been inspected and it supports the results of BER simulation. It has been found that, with increase in spatial separation between LEDs, the deep notches and attenuation in the frequency response of MIMO-VLC system decrease. The overall investigation shows that even though OFDM is resilient to frequency selective fading, an optimum separation between LEDs must be chosen according to the room size for the HPMV system.

Physical Layer Security of In-Home PLC Systems: Analysis Based on a Measurement Campaign

This article investigates the physical layer security (PLS) of a broadband in-home power line communication (PLC) system when a malicious and passive PLC device tries to eavesdrop upon private information sent by a PLC transmitter to a legitimate PLC receiver. In this setting, the ergodic achievable secrecy rate, secrecy outage probability, effective secrecy throughput, and wiretap code rates are numerically evaluated with the use of a data set obtained from a measurement campaign carried out in several Brazilian houses. This data set comprises PLC channel estimates and measured additive noises considering four distinct sets of transmitter, legitimate receiver, and eavesdropper positions. Numerical results, covering three distinct frequency bands (1.7–30 MHz, 1.7–50 MHz, and 1.7–86 MHz), quantitatively show, in practice, the level of vulnerability of broadband in-home PLC systems in terms of PLS and offer some directions for an appropriate design of PLC modems to improve PLS.

Dedicated Energy Harvesting in Concatenated Hybrid PLC-Wireless Systems

This work addresses the use of hybrid power line-wireless channels, which are defined as the concatenation of power line communication (PLC) and wireless communication (WLC) channels, for dedicated energy harvesting purposes in in-home facilities. Based on a measured data set of hybrid PLC-WLC channels, we discuss statistical analyses concerning distinct power masks and two different regions that are associated with typical distances from the electric power grids to the wireless device. Moreover, based on the harvested energy from the hybrid PLC-WLC channels, we report the achievable data rates for data communication through narrowband PLC and WLC channels as well as through the hybrid PLC-WLC channels. The analyses show that feasible values of energy can be harvested from the hybrid PLC-WLC channels and that the high power nature of the PLC noise significantly contributes to the total harvested energy. Finally, we point out that interesting achievable data rates can be attained when the harvested energy is used for data communication purposes.

Cache-Enabled Power Line Communication Networks: Caching Node Selection and Backhaul Energy Optimization

Power line communication (PLC) advances smart grid technology by offering a convenient and efficient data transmission service. However, due to the severe PLC channel condition and ever-growing traffic load in the PLC backhaul, reliable communications among widely distributed in-home PLC users is highly energy-consuming. In this paper, we put forth a cache-enabled PLC network comprising a single master base station (MBS) and mutiple slave base stations (SBSs) each bound with an in-home network to alleviate the backhaul traffic load and reduce the backhaul energy consumption. In the proposed scheme, the SBSs with the local caches pre-download the popular contents from the MBS through the PLC backhaul, and the in-home users request the contents from nearby caching nodes (CNs) or the MBS. Apart from the cache-enabled PLC design, our contributions also lie in the selection of CNs and optimal content placement algorithm. First, we propose a selection algorithm to activate the SBSs with high influence as the CNs, according to a directed graph that models the requesting relations among all SBSs. Second, we design an optimal content placement algorithm to minimize the backhaul energy consumption for the contents with different sizes and user preferences. Simulation results show that our cache-enabled PLC scheme with the caching node selection and optimal content placement can dramatically reduce the backhaul energy consumption, compared with the existing caching strategies.

Narrowband PLC Channel Attenuation Due to a Multi-Grounded Neutral

This paper presents a theoretical study on the influence of a multi-grounded neutral on the transmission of narrowband power-line communication (PLC) signals through a two-wire medium-voltage distribution line. Three different methods are proposed to calculate the transfer function of the line in the 3-500 kHz range: (i) nodal admittance method; (ii) travelling wave method; (iii) electrically-short line approach. The validity, advantages and shortcomings of each method are presented and discussed. It is shown that improving the grounding impedance at the transmitter and receiver locations will contribute to reducing the channel attenuation. It is also shown that the number of intermediate grounding points along the neutral is more relevant for the attenuation of PLC signals than their impedance. In general, increasing such number will always reduce the attenuation in frequencies where the line is electrically short. A similar behavior is observed at the higher end of the 3-500 kHz range provided the grounding interval is less than 300 m, which is half wavelength of the 500 kHz frequency. If the separation between grounding points is greater than that, reducing the number of grounding points is likely to reduce the average channel attenuation, but at the cost of introducing multiple resonant frequencies.

Novel low complexity decoding method for the binary coded frequency shift keying modulation

SummaryThis paper proposes a coded modulation scheme based on frequency shift keying (FSK) modulation and a simple binary permutation code. FSK detection is based on the knowledge of the probability density function (PDF) of the noise and the attenuation of the channel, called FSK “Soft‐Decision” (FSK/SD) detection. We introduce an approximation of the FSK/SD, called FSK “Select Largest” (FSK/SL). We compare the FSK/SL detection with the classical PDF‐based detection techniques, such as FSK/SD and spread‐FSK (SFSK), for both coded and uncoded transmission. As a practical application, we use the power line communication (PLC) channel. We analyze and compare the performances for a narrowband PLC channel with attenuation and impulse noise.

Secure PHY Layer Key Generation in the Asymmetric Power Line Communication Channel

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’s channels are weakly correlated with the intended users’ 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.

Indoor amplify-and-forward power-line and visible light communication channel model based on a semi-hidden Markov model

In this paper, the channel model of a multicarrier, indoor amplify-and-forward (AF) hybrid power-line communication (PLC) and visible light communication (VLC) channel is demonstrated. Measurements are obtained from different positions between the VLC transmitter and receiver in an indoor testbed with the aid of software-defined radios. Using the obtained measurements, channel models are derived using a semi-hidden Markov model (SHMM) with the aid of a Fritchman channel state representation model. The Baum-Welch algorithm is then used to re-estimate and validate the derived models. Results presented show the error-free run distribution in the hybrid channel and the probability of error from the obtained measurements. The re-estimated probability of error (P¯e) of each measured indoor scenario is also seen to match the corresponding measured Pe, showing the validity of the derived SHMM models.

Statistical modeling of magnitudes of Brazilian in-home PLC and hybrid PLC-wireless channels

This paper focuses on the statistical modeling of the magnitudes of frequency responses of Brazilian in-home power line and hybrid power line-wireless in the frequency band from 1.7 up to 100 MHz.122The present work is based on the master thesis (T.F. do A. Nogueira, 2018) [1].In this regard, a method to obtain statistical models is detailed. The statistical modelings of these channels are based on measured data sets, which were acquired through a measurement campaign carried out in Brazilian residences. Numerical results show that Beta and Log-Normal are the best statistical distributions for modeling magnitudes of the frequency responses of Brazilian in-home power line and hybrid power line-wireless communication channels, respectively. Also, these magnitudes are non-stationary random processes.

Energy-minimizing bit allocation for powerline OFDM with multiple delay constraints

We propose a bit-allocation scheme for powerline orthogonal frequency-division multiplexing (OFDM) that minimizes total transmit energy subject to total-bit and delay constraints. Multiple delay requirements stem from different sets of data that a transmitter must time-multiplex and transmit to a receiver. The proposed bit allocation takes into account the channel power-to-noise density ratio of subchannels as well as statistic of narrowband interference and impulsive noise that is pervasive in powerline communication (PLC) channels. The proposed scheme is optimal with 1 or 2 sets of data, and is suboptimal with more than 2 sets of data. However, numerical examples show that the proposed scheme performs close to the optimum. Also, it is less computationally complex than the optimal scheme especially when minimizing total energy over large number of data sets. We also compare the proposed scheme with some existing schemes and find that our scheme requires less total transmit energy when the number of delay constraints is large.

Performance Improvement of PLC Channel Estimator and ASCET Equalizer in a FBMC Transmultiplexer Based on a Multi-Core Solution

Power-Line Communication (PLC) employs multi-carrier modulations, such as Filter-Bank Multi-Carrier (FBMC), to improve communications through the PLC channel and provide an efficient use of the spectrum, thus allowing higher data rates. Since one of the main drawbacks is the noisy channel with multipath and frequency-selective fading, the receiver typically includes a channel estimator and equalizer, at the expense of increasing the computational load and complexity of that receiver and making it difficult to obtain real-time solutions. In this context, this work proposes a heterogeneous System-on-Chip (SoC) architecture for the real-time implementation of a FBMC transmultiplexer that involves the channel estimation and equalization at the reception stage. For that purpose, the performance of a multi-core approach is evaluated for both the Zynq® 7000 SoC and theZynq®UltraScale+ (US+) devices, by using a single-, dual- and quad-core solution to perform the channel estimation and the calculation of the equalizer coefficients in the ARM processor available in the proposed architecture. Two approaches have been analysed for the necessary synchronization among cores; one based on atomic instructions and the other one on interrupts. The dual-core proposal in both Zynq® 7000 and Zynq® US+ provides a x2 acceleration compared to the single-core proposal, whereas the quad-core one inZynq®US+ does not provide a x4 acceleration as expected, due to the timing overheads of the synchronization among cores imposed by the data dependencies existing in these tasks. Experimental results include the evaluation of the processing times for each task in the algorithm, as well as the acceleration obtained by each proposal. The proposed architecture can be easily applied to other processing algorithms that may take advantage of the parallelism provided by the multi-core approach in a more efficient way, depending on their data dependencies.

Harmonic distortion considerations for an integrated WPT-PLC system

AbstractThis paper presents design considerations for an integrated wireless power transfer (WPT) and power line communication (PLC) system (e.g. WPT-PLC). The main goal is to enable wireless charging of mobile electronic products, along with high data rate communication over the shared wireless inductive resonant channel. Starting from a couple of resonant coils, characterized by the S-parameters matrix, the design of an impedance matching network and decoupling filters is carried out to better decouple power and data signals. A pulse-driven class-E power amplifier (PA) and a rectifier are first conceived based on the measured S-parameters and load-pull characterizations. Second, a sine-driven class-E power link, operating at 6.78 MHz, is proposed to reduce the total harmonic distortion of the integrated WPT-PLC system. These design steps aim to ensure high-power efficiency and low harmonic distortion of the class-E PA in order to mildly affect the channel capacity of the PLC. The harmonic interferences of the pulse-driven and sine-driven class-E power links are compared and discussed, together with the electromagnetic compatibility levels, the channel capacity, and the noise disturbances of the PLC channel in order to guarantee an optimized power and data transfer in the integrated WPT-PLC system.

Smart Grid Network With D2D Communication and Coherent PLC: Error Analysis

In this paper, we consider a hybrid smart grid communication network consisting of power line communication (PLC) at the transmitter side and the device-to-device (D2D) cellular communication on the receiver side which provides last mile connectivity. The PLC channel is assumed to experience Rayleigh fading and is corrupted by impulsive noise, and the D2D communication being a short range communication system, is assumed to experience Nakagami- $m$ fading with additive Gaussian noise. We propose a maximal-ratio combining (MRC) receiver for the considered hybrid smart grid communication system employing binary phase shift keying (BPSK) modulation at the transmitter and derive a closed-form symbol error probability (SEP) expression for the proposed receiver. The interference between the D2D links is assumed to be negligible for the tractability of the error probability analysis. Numerical results demonstrate the optimality of operating the D2D links at lower signal-to-noise ratio (SNR) values to overcome the effect of the impulsive PLC channel by utilizing diversity branches.

Cooperative Non-Orthogonal Multiple Access over Log-Normal Power Line Communication Channels

In this paper, we analyze the performance of cooperative power domain non-orthogonal multiple access (NOMA) in power line communication (PLC) networks. Due to the high signal attenuation of the source to user links, a relay aids communication from the source to two users. With half-duplex transmission, the source transmits a superimposed symbol in the first phase. The relay utilizes amplify-and-forward (AF) and decode-and-forward (DF) protocol on the received superimposed signal and forwards it to the users in the second phase. We derive analytic expressions for the outage probability and the system throughput of the proposed system under a PLC log-normal channel with impulsive noise. Based on the results for AF NOMA relaying case, we analyze the system performance at high signal-to-noise ratio (SNR) and derive closed-form lower and upper bounds for the outage probability. Simulation results show an improvement in the outage probability and the system throughput performance of the AF and DF NOMA schemes compared to the NOMA without relaying transmission and conventional orthogonal multiple access scheme. Furthermore, the impact of the channel variance is highlighted in the results. It is shown that the DF NOMA has a better outage probability than the AF NOMA scheme for low channel variance scenarios (i.e., less branches and connected loads in the PLC network). However, as the channel variance increases, AF NOMA scheme has similar outage probability performance as the DF NOMA scheme. In addition, it is shown that the system throughput is enhanced when the relay employs DF relaying compared to AF relaying.

Measurements and Statistical Modelling for Time Behaviour of Power Line Communication Impulsive Noise

This paper proposes a suitable Markov chain stochastic model for the stationary and impulsive noise present in the indoor low-voltage power line communication (PLC) channel in the broadband frequency range of 1-30 MHz, based on extensive measurements. This statistical noise model has three regimes (states) representing background noise, single impulse noise and burst impulse noise. The Markov chain mainly translates the characteristics of PLC noise processes as a catenation of several successive noise impulses, which are consecutively originated in time, producing regular time sample span. When used to produce PLC noise events, the produced data sample sequence proves to conserve the original distribution of the noise measurements with considerable accuracy. In this way, it is considered for examining the time behaviour of PLC noise as a Markov chain with stochastic matrices. From this set of measured data, analytical distribution functions are proposed to model the distribution of measured values. The model enables a more accurate prediction and simulation of PLC system performance and availability.

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

IMPROVING BER PERFORMANCE AND SECURITY IN PLC CHANNEL USING OSTBC, CONVOLUTIONAL CODING AND INTERLEAVING WITH HYBRID SDES-AES ENCRYPTION

This paper aims to improve data security and BER performance in the Power Line Communication channel by using encryption and channel coding techniques. In particular, improvement in BER performance has been obtained while using OSTBC rather than STBC as compared to the results obtained in a previous work. The improved system has been extended to include data security in the PLC channel. In this respect, a Hybrid SDES-AES encryption scheme has been developed. The BER performance of the Hybrid SDES-AES encryption in the PLC channel has been improved by using Convolutional coding, Interleaving and OSTBC. A performance improvement of 11.8 dB has been obtained at a BER of 3×10−5 when compared with the Uncoded Hybrid Encryption case.

A comparative simulation study of different decoding schemes in LDPC coded OFDM systems for NB-PLC channel

In this paper, we study the performance of Low density Parity Check (LDPC) coded orthogonal frequency-division multiplexing (COFDM) systems when they are applied on the short data block of a narrowband (NB) power line communications (PLC) channel. In the modelled system simulations have been performed using different code lengths. It is assumed that the channel has a multipath propagation with two different noise scenarios: AWGN background noise with and without the presence of impulsive noise. Performances of Various soft and hard decision LDPC decoder schemes such as belief propagation (BP), weighted bit flipping (WBF), improved weighted bit flipping (IWBF) and implementation-efficient reliability ratio based weighted bit flipping (IRRWBF) decoders were investigated. It has been shown for all simulations performed in PLC channel model showed that remarkable performance improvement can be achieved by using short-length LDPC codes. Especially, the improvements are striking when the BP decoding algorithms are employed on the receiver side.