Power Line Communication Noise Research Articles

Secrecy Analysis of DCSK-Based PLC Systems With Multiple Eavesdroppers

In the past two decades, chaotic modulation schemes have drawn much attention for their significant advantages over other traditional modulation techniques. One of the noticeable advantages is the capability of providing secure communication in the presence of an eavesdropper. In this article, we study the physical layer security (PLS) performance of low-frequency power line communication (PLC) systems against multiple eavesdroppers by employing differential chaos shift keying based modulation technique. A wiretap power line channel model is investigated by considering two different cases: 1) when all the channels are assumed to be independent and identically distributed (IID) following Log-normal distribution; and 2) the wiretap channels are considered to be identical but correlated Log-normally distributed and independent of the main channel. Contemporaneously, the Bernoulli-Gaussian random process models the PLC noise. Further, a comprehensive PLS study of the considered PLC system is characterized in terms of the average secrecy capacity, secure outage probability, and strictly positive secrecy capacity. We also propose an algorithm to maximize the secrecy throughput under security and reliability constraints. Moreover, to obtain essential insights, we reveal the impact of various crucial parameters onto the proposed system.

PLC Physical Layer Link Identification with Imperfect Channel State Information

This paper proposes an accurate physical layer technique to uniquely identify the links of a power line communication network. First, the power line communications (PLC) multipath channel characterization is presented and detailed. Then, a multipath channel delay detection technique is introduced to provide an accurate physical layer identification (PL ID) for the considered PLC links. The accuracy and efficiency are tested by evaluating the successful path detection probability (SPDP) in a simulated scenario under both perfect and imperfect channel state information conditions. The results confirm the advantages of the proposed scheme. Indeed, for a common PLC noise power around 90 dBuV, the provided accuracy reaches ≈90%, while for a noise power below 80 dBuV, the accuracy plateaus at 100%. Overall, the low complexity of the proposed approach and its staggering performance results pave the way for further possible applications in both the PLC and the security domain.

A noise reduction scheme for OFDM NB-PLC systems

This paper presents a low-complexity noise reduction scheme for orthogonal frequency-division multiplexing (OFDM)-based power line communication (PLC) systems. The solution exploits the positive time-correlation between the subcarrier noise magnitudes and phases. More specifically, we performed field measurements of PLC noise conducted in seven diverse locations, with continuous measurements for two days, covering the 42 kHz to 471 kHz frequency band. After analyzing the data, we have identified a key PLC noise characteristic; the subcarrier noise magnitudes are highly time-correlated in narrow frequency bands. The same behavior has also been noticed for the subcarrier noise phases. This correlation characteristic has been used to propose a simple and efficient noise reduction scheme for NB-PLC systems. We have applied the proposed method in a real case scenario, where PLC noise field measurements have been used to confirm the advantages in terms of noise reduction gain and bit error rate (BER). Indeed, depending on the channel and used modulation, the proposed scheme is able to reduce the BER by around 35 %, in the considered PLC scenarios.

Secrecy Outage Analysis in NOMA Power Line Communications

This letter studies physical layer security (PLS) in non-orthogonal multiple access (NOMA) power line communication (PLC) networks. A source node transmits information to two nodes of near and far users with different power allocations. We consider two different cases of eavesdropping: internal and external. The PLC channel and noise are modeled by correlated log-normal fading and Bernoulli-Gaussian random process, respectively. We derive closed-form expressions for the secrecy outage probability (SOP) of both the internal and external cases by applying Gauss-Chebyshev quadrature, which are verified by Monte Carlo simulations. We observe that higher impulsive noise degrades the SOP while higher channel correlation can improve the SOP. In addition, the analytic results reveal the impact of power allocation on the SOP performance.

Characterization and Exploitation of Quasi Determinism in Multi-Conductor Power Line Communication Noise

Several experiments and field trials have shown that deterministic components characterize the Power Line Communication (PLC) noise across multiple-conductors. This article aims at understanding the main origins of these noise components and evaluate several methods to characterize them statistically. The correlation, distance-correlation, mutual information estimation, and a proposed linear coefficient ratio, are used to analyze the noise time-series statistically. The analysis of the PLC noise deterministic components allow us to develop an enhanced noise model that includes them. The presence of deterministic noise fosters the development of coding and decoding algorithms that aim at mitigating the noise effect. New decoding techniques called Quasi-Deterministic-Decoding are detailed and tested with single-input-multiple-output (SIMO) 1×2 and multiple-input-multiple-output (MIMO) 2×2 transmission configurations using real PLC noise and channel realizations. The proposed model leads to a better representation of the PLC noise traces and, consequently, the development of improved coding algorithms for reliable data transmission at low signal-to-noise ratios.

Hybrid forward error correction coding efficiency for MIMO-PLC with symmetric alpha-stable noise

Power line communication (PLC) medium is a very hostile environment, this is due to the fact that severe impairments adhering this means of communication, which cannot be described as a Gaussian noise. In this paper, we propose a powerful scheme to combat the impulsive noise effect and efficiently increase the transmission bit rate. The proposed technique makes use of a new hybrid coding (HC) process and a multiple input multiple output (MIMO) based orthogonal frequency division multiplexing (OFDM), namely, HC-MIMO-OFDM. The HC is mainly constructed based on the combination of convolutional codes (CC) and quasi cyclic-low density parity check codes (QC-LDPC). The HC-MIMO-OFDM stage is then followed by an orthogonal space time block code to provide more robustness under a heavy impulsive noise environment. Furthermore, the symmetric $$\alpha $$-stable model is applied to characterize the realistic PLC noise and consequently avoid the overestimation of the overall performance in such communication systems. The obtained results showed the increase improvement in performance of the bit-error-rate with the raise of the bit rate, when going from single input single output to MIMO. In addition, it has been illustrated that there was a gain when the MIMO was supplemented with only the CC and an additional gain when the HC is considered (i.e., combination of CC plus QC-LDPC coding).

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.

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.

Two-Stage Non-Orthogonal Multiple Access Over Power Line Communication Channels

Non-orthogonal multiple access (NOMA) has recently been proposed for dual-hop cooperative relaying power line communication (PLC) systems. Unlike conventional NOMA-PLC schemes which deploy NOMA only at the relay, this paper proposes to enhance the performance of such systems by implementing the principle of NOMA at both the source and relaying modems. The system performance is evaluated in terms of the average sum capacity for which analytical expressions are derived for both the improved and conventional NOMA-PLC systems. Throughout our analysis, the PLC channel is assumed narrow-band modeled with log-normal amplitude distribution and the total PLC noise consists of both background and impulsive noise. Monte Carlo simulations are provided to corroborate the accuracy of our theoretical analysis. The derived expressions are utilized to examine the impact of various system parameters on the average capacity performance; this includes: impulsive noise probability, network branching, power allocation coefficients, and transmit power. The optimization problem of the power allocation coefficients is also addressed for both NOMA-PLC systems under consideration. Results reveal that significant gains in the average capacity can be attained with the improved NOMA-PLC approach compared to the conventional system. In addition, the improved system is able to meet a given performance requirement with smaller transmit power offering more relaxed electromagnetic compatibility issues associated with PLCs. Finally, it is demonstrated that optimizing the power allocation coefficients at both the source and relay modems is crucial to maximize performance.

Analysis of Bursty Impulsive Noise in Low-Voltage Indoor Power Line Communication Channels: Local Scaling Behaviour

Power line communication (PLC) channels are prone to multipath propagation due to impedance mismatch, and impulsive noise whose characteristics are still not well established in the literature. Moreover, measurements show that this impulsive noise appear in bursts, non-Gaussian and cyclostationary and as such cannot be modeled as the convenient additive white Gaussian noise (AWGN). Transceivers optimized for AWGN may not necessarily perform well for the PLC noise. Therefore, investigating the characteristics of PLC noise is very important for accurate modeling of the same. This study presents multifractal analysis of bursty impulsive noise measured from power line networks from three different environments. We employ multifractal detrended fluctuation analysis, which is a well-developed multifractal analysis technique for non-stationary time series data and easy to implement to analyze measured noise data. Results show that power line noise exhibits both long-range dependence (LRD) and multifractal scaling behavior with different strengths depending on the environments where they were captured. The multiscaling behavior is due to long-range correlation inherent in the power line noise. The source of this local multiscaling behavior is determined by analysis a shuffled series of the original data captured from the power network. Multifractal analysis is able to show clearly both the strengths and frequency of occurrence of bursts occurring in PLC noise which can then be applied in accurate modeling of the noise. The significance of these results is that new power line noise models should be developed that captures both LRD and multifractal scaling for more accurate performance evaluation of power line communication systems. The existing noise models though able to replicate temporal dependence of PLC noise, are not able to capture this local scaling behavior which results show is inherent in PLC noise.

On Companding and Optimization of OFDM Signals for Mitigating Impulsive Noise in Power-Line Communication Systems

Generally, the probability density function (PDF) of orthogonal frequency division multiplexing (OFDM) signal amplitudes follow the Rayleigh distribution, thus, it is difficult to correctly predict the existence of impulsive noise (IN) in powerline communication (PLC) systems. Compressing and expanding the amplitudes of some of these OFDM signals, usually referred to as companding, is a peak-to-average power ratio reduction technique that distorts the amplitudes of OFDM signals towards a uniform distribution. We suggest its application in PLC systems, such as IEEE 1901 powerline standard (which uses OFDM) to reduce the impacts of IN. This is because the PLC channel picks up impulsive interference that the conventional OFDM driver cannot combat. We explore, therefore, five widely used companding schemes that convert the OFDM signal amplitude distribution to uniform distribution to avail the mitigation of IN in PLC system receivers by blanking, clipping and their hybrid (clipping-blanking). We also apply nonlinear optimization search to find the optimal mitigation thresholds and results show significant improvement in the output signal-to-noise ratio (SNR) for all companding transforms considered of up to 4 dB SNR gain. It follows that the conventional PDF leads to false IN detection, which diminishes the output SNR when any of the above three nonlinear memoryless mitigation schemes is applied.

Improving bit error rate under burst noise in OFDM power line communications

Noise in Power Line Communications is typically impulsive, with impulses being a fraction of the OFDM symbol length. Because of their large duration the impulse can also be called bursts. The short duration of the burst compared with the OFDM symbol length implies that there is a strong correlation between the noise at different carriers, given a determined burst position. The position can be determined using an estimate of the noise after a first demodulation. The high correlation is used to develop demodulators with a reduced bit error rate in comparison with conventional demodulators, so increasing the capacity. The demodulators use a smoothed estimate of the noise signal or a new metric for the distance based on the new correlation matrix. About half of the bit errors can be corrected in this way, corresponding to a 1 dB improvement in Signal Noise Ratio (SNR). How to split the OFDM symbol without increasing the overhead due to the circular prefix is also shown. Noise measurements in power lines are presented. These measurements are used in the simulations.

OFDM-based power-line communication enhancement using a turbo coded adaptive impulsive noise compensator

In this paper, we propose a novel estimation and decoding scheme for power-line communication (PLC) systems in impulsive noise environments. The proposed scheme is based on the turbo coding combined with adaptive noise compensation to reduce burst errors and multipath effects. For this purpose, the PLC channel and noise models are introduced, then, the turbo encoder/decoder are inserted in the mapper/demapper and the pilot insertion block for the sake of enhancing preliminary estimation of the transmitted orthogonal frequency division multiplexing signals. The proposed impulsive noise compensator is based on the estimation of the impulse bursts using a new blanking/clipping function, and on the estimation of the signal to impulse noise ratio and the peak to average power ratio. Simulation results illustrate that receivers with combined turbo coding and the proposed noise compensator drastically outperform existing receivers under impulsive noise. In comparison to some existing schemes, the proposed scheme reaches its perfect performance in a reduced 15-paths environment, when the bit error rate and mean square error performance are tested. The improvements in SNR performance are more than 16 dB for BPSK modulation and can reach 12---20 dB for 16-QAM modulation, when a high impulsive noise level is considered.

MIMO Power Line Communications

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 paper 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. In addition, MIMO signal processing techniques most suited to PLC environments are discussed, allowing for throughput predictions. It is found that eigenbeam-forming 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 PLC configuration to a 2 × 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.

Bit error rate of RS coded BFSK in broadband powerline channels with background Nakagami and impulsive noise

Power line communication (PLC) systems are being standardized over the globe and some of these standards recommended frequency shift keying (FSK) as their modulation choice. Broadband transmission over a PLC channel is mainly affected by the ever-present background noise and the occasional high-amplitude impulses. It has been recently found that the background noise in PLC can be suitably modelled with Nakagami-m distribution while a standard model for characterizing impulses is to assume Gaussian distributed amplitude and Poisson distributed arrivals. Considering such a model, at first, simple analytical bit error rate (BER) expressions of uncoded binary FSK (BFSK) signals are derived in the paper. The derived expressions are simple, involve only elementary functions, and the analytical BER values match perfectly with computer simulations. Next, a unified analytical framework is presented for evaluating BER when a Reed Solomon (RS) code is used to mitigate the noise effects. The results reveal that when the signal to background noise ratio (SBNR) is low, there is a clear impact of the noise parameter m and the choice of demodulation method (coherent/ non-coherent) on the error performance of the coded system. On the contrary, at higher SBNR, impulsive noise dominates over background noise, and these effects vanish as the BER curves become flat. Numerical evaluations dictated that by allowing a lower code rate (0.7) this error floor may be reduced significantly (up to 10−15). Further, the code gain of the system was found to be an inverse function of the code rate and codeword length.

PLC Performance Analysis Over Rayleigh Fading Channel Under Nakagami- <inline-formula> <tex-math notation="TeX">$m$</tex-math></inline-formula> Additive Noise

Power line communication (PLC) utilizes power lines for transmission of power as well as data transmission. It is an emerging field of communication for the home area network of smart grid. The performance of a PLC system is significantly affected by the additive and multiplicative power line noises; the additive noises are of two types, namely background noise and impulsive noise. Whereas, the multiplicative PLC noise leads to fading in the received signal strength. This paper provides the performance analysis of a PLC system over Rayleigh fading channel under Nakagami- $m$ distributed additive background noise assuming binary phase shift keying modulation scheme. The probability density function of the decision variable is derived. We obtain a numerically computable expression of the analytical average bit error rate of the considered system. The closed-form expression of the outage probability of the PLC system is also computed. Simulation results closely verify the validity of the derived analytical expressions.

Modeling Of Power Line Communication Channel For Automatic Meter Reading System With LDPC Codes

In this era of modernization, one of the promising emerging technologies is Power Line Communication (PLC) system. In previous research fields, modeling of PLC channel, mostly for indoor applications has been studied. However, the need to study that for outdoor applications, such as the Automatic Meter Reading (AMR) systems is also vital. Moreover, standardization bodies have considered the use of LDPC codes restricted for indoor systems. Thus, in this paper, not only we model the PLC channel based on AMR applications, but also, we apply LDPC coding scheme to the system. To accomplish the objectives, firstly, we model the PLC-AMR channel, which includes multipath phenomenon. Additionally, PLC noise, usually occurring in the channel, is modeled. The modulation technique applied is BPSK and the performance of the system with varying load impedances is compared. The coded system consists of irregular LDPC codes, with two different constructions of the Parity-Check matrix, namely that by Radford Neal and reduced size of DVBS2. The performances of respective systems are then compared. Using LDPC by Radford Neal, the performances are analyzed with varied code rates. Keywords—Power Line Communication; Automatic meter reading;

Deep Clipping for Impulsive Noise Mitigation in OFDM-Based Power-Line Communications

Nonlinear preprocessors, including clipping, blanking, and joint blanking/clipping have been proposed to be employed in orthogonal frequency-division multiplexing systems for mitigating the impulsive noise in power-line communications. In this paper, we propose using a new variant of nonlinear preprocessor, namely, deep clipping, to mitigate the impulsive noise. In contrast to clipping, blanking, and joint blanking/clipping, where one or two thresholds is used to detect if the impulsive noise occurs, and if the impulsive noise occurs how to handle it, deep clipping is characterized by two alternative parameters, namely, a threshold and a depth factor. By optimizing the two parameters, we find that deep clipping achieves better signal-to-noise ratio (SNR) performance than clipping, blanking, and joint blanking/clipping. In addition, we present a mathematical expression for deep clipping and show that the SNR expressions regarding conventional clipping, blanking, and joint blanking/clipping can be easily obtained by using our analytical methods.

Optimised resource allocation under impulsive noise in power line communications

Power lines render very harsh and hostile environment for electronic data communication. The key characteristics of the power line channel are time varying nature, frequency selective attenuation and presence of impulsive noise because of random switching of power appliances. The impulsive nature of the additive noise has been ignored so far in the literature for resource allocation in power line communication system because this assumption results in intractable solutions. In this study, an approach of efficient resource allocation is introduced in order to maximise the throughput and achieve tolerable bit error rate of the power line system, by adapting power transmitted in each cycle, under additive Middleton class A impulsive noise (MCAIN). The proposed resource allocation technique utilises sub-channel ordering to obtain a higher throughput; and provides improvement as compared to the existing zero forcing based resource allocation technique under additive MCAIN.

A Fractional Lower Order Statistics-Based MIMO Detection Method in Impulse Noise for Power Line Channel

Impulse noise in power line communication (PLC) channel seriously degrades the performance of Multiple-Input Multiple-Output (MIMO) system. To remedy this problem, a MIMO detection meth ...