Impact of Channel Disturbances on Current Narrowband Power Line Communications and Lessons to Be Learnt for the Future Technologies

[EN] The electricity network is a complex communication medium with properties that depend on both the topology of the grid and the usage pattern of the connected devices. These devices generate channel disturbances during normal operation, which need to be overcome by power line communications (PLC) transmission technologies for ensuring communication. This paper analyzes the influence of the channel disturbances on the performance of the physical layer of the main narrowband PLC technologies approved by international communication organisms and currently deployed in Europe: PoweRline Intelligent Metering Evolution (PRIME) 1.3.6, PRIME 1.4 and G3-PLC. The methodology of this paper applies a standardized test method, metrics and a set of representative channel disturbances defined by the European Telecommunications Standards Institute (ETSI). Moreover, noise recordings from field measurements in an environment equipped with distributed energy resources (DER) complete the subset of the types of noise used in the study. This paper develops a replicable, fully automated, and cost optimized test scenario, based on an innovative Virtual PLC Laboratory, which provides a replicable and automated test process, where a wide range of channel disturbances can be accurately replicated, and the performance of the PLC technologies can be compared under the same conditions. The results of this paper provide important conclusions to be applied in the development of future PLC technologie

Enhanced Performance of Narrowband Power Line Communications using Recursive Least Squares Filter

Noises presented in a power line communication channel tend to distort the message signals, leading towards the reception of erroneous data at the receiver end. Mitigation of noise existent in power line has always been of prime interest and helped to improve the BER performance of a communication system as it accounts for efficient data transmission. In this work, adaptive filters based on the Recursive Least Squares (RLS) algorithm and Least Mean Square (LMS) algorithms have been implemented in Simulink to investigate the effectiveness of an Adaptive Noise Canceller for the mitigation of Gaussian and Impulsive Noises present in a narrowband power line channel model. The performance of the RLS algorithm against that of the LMS algorithm was compared in adaptive filtering for the same channel conditions. The error performances of BPSK and FSK schemes for the channel model in a generic digital communication system were also compared in Simulink. Furthermore, the use of convolutional codes and interleaving for the correction of random bit errors and for condensing the negative effect of burst errors respectively were investigated during the transmission of data signals over the generic communication system designed in Simulink. From the findings of the study, it has been concluded that the RLS algorithm proves to be more effective than the LMS algorithm. For a BER of 10-5, a coding gain of less than 10 dB is achievable for both Binary Phase Shift Keying and Binary Frequency Shift Keying. With the addition of convolutional coding and convolutional interleaving, the error performance of the channel is further improved, rendering the power line channel more reliable for data communication

Applications of artificial intelligence in powerline communications in terms of noise detection and reduction : a review

Abstract: The technology which utilizes the power line as a medium for transferring information known as powerline communication (PLC) has been in existence for over a hundred years. It is beneficial because it avoids new installation since it uses the present installation for electrical power to transmit data. However, transmission of data signals through a power line channel usually experience some challenges which include impulsive noise, frequency selectivity, high channel attenuation, low line impedance etc. The impulsive noise exhibits a power spectral density within the range of 10-15 dB higher than the background noise, which could cause a severe problem in a communication system. For better outcome of the PLC system, these noises must be detected and suppressed. This paper reviews various techniques used in detecting and mitigating the impulsive noise in PLC and suggests the application of machine learning algorithms for the detection and removal of impulsive noise in power line communication systems

Mitigation of impulse noise in powerline systems using ANFIS technique

Abstract: The use of OFDM channel for the transmission of data in power line communication (PLC) system has been of several importance to technology development. However, during transmission, the OFDM channel is greatly disturbed by impulse noise that causes a wrong information to be received. Several techniques such as iteration, coding, clipping and nulling methods have been used to lessen the upshot of impulse noise in OFDM channel. However, these techniques still suffer some drawbacks and require a high signal-to-noise (SNR) power for high performance. This paper presents an advanced use of artificial neuro-fuzzy inference system (ANFIS) technique in removing the complete impulse noise and some of the additive white Gaussian noise (AWGN) that were mixed with the transmitted data in an OFDM channel and using the minimum SNR power. Obtained results propose that ANFIS technique can be used to mitigate impulse noise from a powerline communication channel

Emulation of Narrowband Powerline Data Transmission Channels and Evaluation of PLC Systems

This work proposes advanced emulation of the physical layer behavior of NB-PLC channels and the application of a channel emulator for the evaluation of NB-PLC systems. In addition, test procedures and reference channels are proposed to improve efficiency and accuracy in the system evaluation and classification. This work shows that the channel emulator-based solution opens new ways toward flexible, reliable and technology-independent performance assessment of PLC modems

Investigation of Orthogonal Frequency Division Multiplexing Based Power Line Communication Systems

Power Line Communication (PLC) has the potential to become the preferred technique for providing broadband to homes and offices with the advantage of eliminating the need for new wiring infrastructure and reducing the cost. Power line grids, however, present a hostile channel for data communication, since the fundamental purpose of the power line channel was only the transmission of electric power at 50/60 Hz frequencies. The development of PLC systems for providing broadband applications requires an adequate knowledge of the power line channel characteristics. Various types of noise and multipath effects are some of the limitations for power line channels which need to be considered carefully in designing PLC systems. An effect of an impulsive noise characterized with short durations is identified as one of the major impairment in PLC system. Orthogonal Frequency Division Multiplexing (OFDM) technique is one of the modulation approaches which has been regarded as the modulation technique for PLC systems by most researchers in the field and is used in this research study work. This is because it provides high robustness against impulsive noise and minimizes the effects of multipath. In case of impulsive noise affecting the OFDM system, this effect is spread over multiple subcarriers due to Discrete Fourier Transform (DFT) at the receiver. Hence, each of the transmitted communication symbols is only affected by a fraction of the impulsive noise. In order to achieve reliable results for data transmission, a proper power line channel with various noise models must be used in the investigations. In this research study work, a multipath model which has been widely accepted by many researchers in the field and practically proven in the Tanzanian power line system is used as the model for the power line channel. The effects of different scenarios such as variations in direct path length, path number, branch length and load on the channel frequency response are investigated in this research work. Simulation results indicate the suitability of multi-carrier modulation technique such as an OFDM over the power line channels. To represent the actual noise scenario in the power line channel, an impulsive noise and background noise are classified as the two main noise sources. A Middleton class A noise is modelled as an impulsive noise, whereas the background noise is modelled as an Additive White Gaussian Noise (AWGN). The performance of PLC system based on OFDM is investigated under Middleton Class A and AWGN noise scenarios. It is observed that Bit Error Rate (BER) for the impulsive noise is higher than the background noise. Since channel coding can enhance the transmission in a communication system, Block code and convolutional codes have been studied in this research work. The hamming code chosen as a type of the block code, whereas the Trellis Coded Modulation (TCM) selected from the category of the convolutional channel codes and modelled in Matlab2013b. Although TCM code produces improvements in the Signal-to-Noise Ratio (SNR), they do not perform well with Middleton class A noise. A rectangular 16-QAM TCM based on OFDM provides better BER rate compared to the general TCM

Transmission of compressed images over power line channel

In the telecommunications industry, the use of existing power lines has drawn the attention of many researchers in the recent years. PLC suffers from impulsive noise that can affect data transmission by causing bit or burst errors. In this thesis, PLC channel was used as a transmission scheme to transmit compressed still images using FFT-OFDM. When lossy compression is applied to an image, a small loss of quality in the compressed image is tolerated. One of the challenging tasks in image compression and transmission is the trade-off between compression ratio and image quality. Therefore, we utilized the latest developments in quality assessment techniques, SSIM, to adaptively optimize this trade-off to the type of image application which the compression is being used for. A comparison between different compression techniques, namely, discrete cosine transform (DCT), discrete wavelet transform (DWT), and block truncation coding (BTC) was carried out. The performance criteria for our compression methods include the compression ratio, relative root-meansquared (RMS) error of the received data, and image quality evaluation via structural similarity index (SSIM). Every link in a powerline has its own attenuation profile depending on the length, layout, and cable types. Also, the influences of multipath fading due to reflections at branching point vary the attenuation profile of the link. As a result, we observed the effect of different parameters of the PLC channel based on the number of paths, and length of link on the quality of the image. Simulations showed that the image quality is highly affected by the interaction of the distance of PLC channel link and the number of multipath reflections. The PLC channel is assumed to be subjected to Gaussian and impulsive noises. There are two types of impulsive noise: asynchronous impulsive noise and periodic impulsive noise synchronous to the mains frequency. BER analysis was performed to compare the performance of the channel for the two types of impulsive noise under three impulsive scenarios. The first scenario is named as "heavily disturbed" and it was measured during the evening hours in a transformer substation in an industrial area. The second scenario is named as "moderately disturbed" and was recorded in a transformer substation in a residential area with detached and terraced houses. The third scenario is named as "weakly disturbed" and was recorded during night-time in an apartment located in a large building. The experiments conducted showed that both types of noise performed similarly in the three impulsive noise scenarios. We implemented Bose-Chaudhuri-Hocquenghen (BCH) coding to study the performance of Power Line Channel (PLC) impaired by impulsive noise and AWGN. BCH codes and RS codes are related and their decoding algorithms are quite similar. A comparison was made between un-coded system and BCH coding system. The performance of the system is assessed by the quality of the image for different sizes of BCH encoder, in three different impulsive environments. Simulation results showed that with BCH coding, the performance of the PLC system has improved dramatically in all three impulsive scenarios

Reports on industrial information technology. Vol. 12

The 12th volume of Reports on Industrial Information Technology presents some selected results of research achieved at the Institute of Industrial Information Technology during the last two years.These results have contributed to many cooperative projects with partners from academia and industry and cover current research interests including signal and image processing, pattern recognition, distributed systems, powerline communications, automotive applications, and robotics