Masreliez-Equalized VOFDM in Non-Gaussian Channels: Power Line Communication Systems

In this paper, we derive a non-linear equalizer for a fading channel with non-Gaussian noise. In particular, we look into the effects of non-Gaussian noise over power line channels that severely affect communication signals. Unlike most existing work based on orthogonal frequency-division multiplexing (OFDM) in the literature, we investigate the performance of vector OFDM (VOFDM) over multi-path power line communication (PLC) channels contaminated with Middleton Class-A noise. To reduce the impact of impulsive noise we propose a novel filter to equalize the output of the channel. The performance of the equalizer is evaluated in terms of bit error rate (BER), and the impact of several impulsive noise parameters are examined at the receiver. Results show that the proposed system can considerably improve the BER performance in comparison to the conventional OFDM scheme. In addition, it is shown that increasing the number of vector blocks of the VOFDM system will enhance the BER performance under the same condition. The proposed non-linear equalizer improves the performance of VOFDM system successfully at low signal-to-noise ratios (SNRs), at some instances it nearly halved the probability of error with respect to linear filter

Vector OFDM Transmission over Non-Gaussian Power Line Communication Channels

Most of the recent power line communication (PLC) systems and standards, both narrow-band and broadband, are based on orthogonal frequency-division multiplexing (OFDM). This multiplexing scheme, however, suffers from the high peak-to-average power ratio (PAPR), which can considerably impact the energy efficiency, size, and cost of PLC modems as well as cause electromagnetic compatibility (EMC) issues. This paper investigates the performance of vector OFDM (VOFDM), which has inherently better PAPR properties, over non-Gaussian broadband PLC channels equipped with two nonlinear preprocessors at the receiver. In addition, the low PAPR property of the VOFDM system is exploited to further enhance the efficiency of the nonlinear preprocessors. The achievable gains are studied in terms of the complementary cumulative distribution function of the PAPR, probability of noise detection error, and the signal-to-noise ratio at the output of the nonlinear preprocessors. For comparison’s sake, the performance of conventional OFDM systems is also presented throughout this paper. Results reveal that the proposed system is able to provide up to 2-dB saving in the transmit power relative to the conventional OFDM under same system conditions, which eventually also translates into a system that is more resilient to EMC limits, reduced cost, and size of PLC modems. It is also shown that the achievable gains become more significant as the vector block size of the VOFDM system is increased

Laboratory and field evaluation of three low-cost particulate matter sensors

Low-cost off-the-shelf particulate matter (PM) sensors have the potentiality to be used for evaluating the air quality in outdoor settings. Monitoring of air quality in surface coal mines is an example of such applications. In coal mines, long-term exposure to inhalation of coal dust is harmful and can lead to coal workers' pneumoconiosis, which is a potentially disabling lung disease. Therefore, continual monitoring of air quality in coal mines is a must and vital and can potentially assist in preventing such diseases. Although, using and deploying of the existing low-cost and lightweight sensors can help to improve monitoring resolution in a much cost-effective manner, there are some concerns regarding the reliability of the collected data from these sensors. Therefore, low-cost PM sensors are required to initially be compared with the standard reference instruments and then be calibrated. In this study, three different types of low-cost, light-scattering-based widely available PM sensors (Shinyei PPD42NS, Sharp GP2Y1010AU0F and Laser SEN0177) are evaluated, compared, and calibrated with the reference instruments in a controlled environment as well as in a field experiment (surface coal mineLow-cost off-the-shelf particulate matter (PM) sensors have the potentiality to be used for evaluating the air quality in outdoor settings. Monitoring of air quality in surface coal mines is an example of such applications. In coal mines, long-term exposure to inhalation of coal dust is harmful and can lead to coal workers' pneumoconiosis, which is a potentially disabling lung disease. Therefore, continual monitoring of air quality in coal mines is a must and vital and can potentially assist in preventing such diseases. Although, using and deploying of the existing low-cost and lightweight sensors can help to improve monitoring resolution in a much cost-effective manner, there are some concerns regarding the reliability of the collected data from these sensors. Therefore, low-cost PM sensors are required to initially be compared with the standard reference instruments and then be calibrated. In this study, three different types of low-cost, light-scattering-based widely available PM sensors (Shinyei PPD42NS, Sharp GP2Y1010AU0F and Laser SEN0177) are evaluated, compared, and calibrated with the reference instruments in a controlled environment as well as in a field experiment (surface coal mineAlpha Foundation for the Improvement of Mine Safety and Health. Grant Number: Grant Number AFC417-39Alpha Foundation for the Improvement of Mine Safety and Health. Grant Number: Grant Number AFC417-3