Power line communications over time-varying frequency-selective power line channels for smart home applications

Many countries in the world are developing the next generation power grid, the smart grid, to combat the ongoing severe environmental problems and achieve e�cient use of the electricity power grid. Smart metering is an enabling technology in the smart grid to address the energy wasting problem. It monitors and optimises the power consumption of consumers' devices and appliances. To ensure proper operation of smart metering, a reliable communication infrastructure plays a crucial role. Power line communication (PLC) is regarded as a promising candidate that will ful�l the requirements of smart grid applications. It is also the only wired technology which has a deployment cost comparable to wireless communication. PLC is most commonly used in the low-voltage (LV) power network which includes indoor power networks and the outdoor LV distribution networks. In this thesis we consider using PLC in the indoor power network to support the communication between the smart meter and a variety of appliances that are connected to the network. Power line communication (PLC) system design in indoor power network is challenging due to a variety of channel impairments, such as time-varying frequency-selective channel and complex impulsive noise scenarios. Among these impairments, the timevarying channel behaviour is an interesting topic that hasn't been thoroughly investigated. Therefore, in this thesis we focus on investigating this behaviour and developing a low-cost but reliable PLC system that is able to support smart metering applications in indoor environments. To aid the study and design of such a system, the characterisation and modelling of indoor power line channel are extensively investigated in this thesis. In addition, a exible simulation tool that is able to generate random time-varying indoor power line channel realisations is demonstrated. Orthogonal frequency division modulation (OFDM) is commonly used in existing PLC standards. However, when it is adopted for time-varying power line channels, it may experience signi�cant intercarrier interference (ICI) due to the Doppler spreading caused by channel time variation. Our investigation on the performance of an ordinary OFDM system over time-varying power line channel reveals that if ICI is not properly compensated, the system may su�er from severe performance loss. We also investigate the performance of some linear equalisers including zero forcing (ZF), minimum mean squared error (MMSE) and banded equalisers. Among them, banded equalisers provide the best tradeo� between complexity and performance. For a better tradeo� between complexity and performance, time-domain receiver windowing is usually applied together with banded equalisers. This subject has been well investigated for wireless communication, but not for PLC. In this thesis, we investigate the performance of some well-known receiver window design criteria that was developed for wireless communication for time-varying power line channels. It is found that these criteria do not work well over time-varying power line channels. Therefore, to �ll this gap, we propose an alternative window design criterion in this thesis. Simulations have shown that our proposal outperforms the other criteria

Sparsity-Based Joint NBI and impulse noise mitigation in hybrid PLC-Wireless transmissions

We propose a new sparsity-aware framework to model and mitigate the joint effects of narrow-band interference (NBI) and impulsive noise (IN) in hybrid powerline and unlicensed wireless communication systems. The proposed mitigation techniques, based on the principles of compressive sensing, exploit the inherent (non-contiguous or contiguous) sparse structures of NBI and IN in the frequency and time domains, respectively. For the non-contiguous NBI and IN, we develop a multi-level orthogonal matching pursuit recovery algorithm that exploits prior knowledge about the sparsity level at each receive antenna and powerline to further reduce computational complexity without performance loss. In addition, for the non-contiguous asynchronous NBI scenario, we investigate the application of time-domain windowing to enhance the NBI's sparsity and, hence, improve the NBI mitigation performance. For the contiguous NBI and IN scenario, we estimate the NBI and IN signals by modeling their burstiness as block-sparse vectors with and without prior knowledge of the bursts' boundaries. Moreover, we show how to exploit the spatial correlations of the NBI and IN across the receive antennas and powerlines to convert a non-contiguous NBI and IN problem to a block-sparse estimation problem with much lower complexity. Furthermore, we investigate a Bayesian linear minimum mean square error-based approach for estimating both non-contiguous and contiguous NBI and IN based on their second-order statistics to further improve the estimation performance. Finally, our numerical results illustrate the superiority of the joint processing of our proposed NBI and IN sparsity-based mitigation techniques compared to separate processing of the wireless and powerline received signals. 2013 IEEE.This work was supported by NPRP through the Qatar National Research Fund (a member of Qatar Foundation) under Grant NPRP 8-627-2-260.Scopu

Power line communications over time-varying frequency-selective power line channels for Smart Home Applications

Many countries in the world are developing the next generation power grid, the smart grid, to combat the ongoing severe environmental problems and achieve e�cient use of the electricity power grid. Smart metering is an enabling technology in the smart grid to address the energy wasting problem. It monitors and optimises the power consumption of consumers' devices and appliances. To ensure proper operation of smart metering, a reliable communication infrastructure plays a crucial role. Power line communication (PLC) is regarded as a promising candidate that will ful�l the requirements of smart grid applications. It is also the only wired technology which has a deployment cost comparable to wireless communication. PLC is most commonly used in the low-voltage (LV) power network which includes indoor power networks and the outdoor LV distribution networks. In this thesis we consider using PLC in the indoor power network to support the communication between the smart meter and a variety of appliances that are connected to the network. Power line communication (PLC) system design in indoor power network is challenging due to a variety of channel impairments, such as time-varying frequency-selective channel and complex impulsive noise scenarios. Among these impairments, the timevarying channel behaviour is an interesting topic that hasn't been thoroughly investigated. Therefore, in this thesis we focus on investigating this behaviour and developing a low-cost but reliable PLC system that is able to support smart metering applications in indoor environments. To aid the study and design of such a system, the characterisation and modelling of indoor power line channel are extensively investigated in this thesis. In addition, a exible simulation tool that is able to generate random time-varying indoor power line channel realisations is demonstrated. Orthogonal frequency division modulation (OFDM) is commonly used in existing PLC standards. However, when it is adopted for time-varying power line channels, it may experience signi�cant intercarrier interference (ICI) due to the Doppler spreading caused by channel time variation. Our investigation on the performance of an ordinary OFDM system over time-varying power line channel reveals that if ICI is not properly compensated, the system may su�er from severe performance loss. We also investigate the performance of some linear equalisers including zero forcing (ZF), minimum mean squared error (MMSE) and banded equalisers. Among them, banded equalisers provide the best tradeo� between complexity and performance. For a better tradeo� between complexity and performance, time-domain receiver windowing is usually applied together with banded equalisers. This subject has been well investigated for wireless communication, but not for PLC. In this thesis, we investigate the performance of some well-known receiver window design criteria that was developed for wireless communication for time-varying power line channels. It is found that these criteria do not work well over time-varying power line channels. Therefore, to �ll this gap, we propose an alternative window design criterion in this thesis. Simulations have shown that our proposal outperforms the other criteria

Power line communications over time-varying frequency-selective power line channels for smart home applications

Many countries in the world are developing the next generation power grid, the smart grid, to combat the ongoing severe environmental problems and achieve e�cient use of the electricity power grid. Smart metering is an enabling technology in the smart grid to address the energy wasting problem. It monitors and optimises the power consumption of consumers' devices and appliances. To ensure proper operation of smart metering, a reliable communication infrastructure plays a crucial role. Power line communication (PLC) is regarded as a promising candidate that will ful�l the requirements of smart grid applications. It is also the only wired technology which has a deployment cost comparable to wireless communication. PLC is most commonly used in the low-voltage (LV) power network which includes indoor power networks and the outdoor LV distribution networks. In this thesis we consider using PLC in the indoor power network to support the communication between the smart meter and a variety of appliances that are connected to the network. Power line communication (PLC) system design in indoor power network is challenging due to a variety of channel impairments, such as time-varying frequency-selective channel and complex impulsive noise scenarios. Among these impairments, the timevarying channel behaviour is an interesting topic that hasn't been thoroughly investigated. Therefore, in this thesis we focus on investigating this behaviour and developing a low-cost but reliable PLC system that is able to support smart metering applications in indoor environments. To aid the study and design of such a system, the characterisation and modelling of indoor power line channel are extensively investigated in this thesis. In addition, a exible simulation tool that is able to generate random time-varying indoor power line channel realisations is demonstrated. Orthogonal frequency division modulation (OFDM) is commonly used in existing PLC standards. However, when it is adopted for time-varying power line channels, it may experience signi�cant intercarrier interference (ICI) due to the Doppler spreading caused by channel time variation. Our investigation on the performance of an ordinary OFDM system over time-varying power line channel reveals that if ICI is not properly compensated, the system may su�er from severe performance loss. We also investigate the performance of some linear equalisers including zero forcing (ZF), minimum mean squared error (MMSE) and banded equalisers. Among them, banded equalisers provide the best tradeo� between complexity and performance. For a better tradeo� between complexity and performance, time-domain receiver windowing is usually applied together with banded equalisers. This subject has been well investigated for wireless communication, but not for PLC. In this thesis, we investigate the performance of some well-known receiver window design criteria that was developed for wireless communication for time-varying power line channels. It is found that these criteria do not work well over time-varying power line channels. Therefore, to �ll this gap, we propose an alternative window design criterion in this thesis. Simulations have shown that our proposal outperforms the other criteria

Multichannel power line communication

Power line communication (PLC) is the technology in which the data signals of a communication system are transmitted through the conductors of a power delivery infrastructure. The unique environment of the PLC channels create specific challenges and requirements, which need to be modeled and analyzed properly in order to obtain a clear understanding of the communication system as well as attaining the ability to further improve the performance and reliability of the transmission. Moreover, the demand for increased data throughput as well as increased reliability and robustness of the transmission is of fundamental importance in any communication system as it is in PLC systems. In order to address these challenges and demands, the concept of multichannel PLC is studied and developed in this thesis. Multichannel PLC in this context is referred to the transmission of multiple information-carrying signals though the power line channel from one source to one destination. We study multiple scenarios of multichannel data transmission in order to cover the diverse situations and requirements of a PLC transmission. One of the multichannel scenarios discussed in this thesis is the multiple-input multiple-output (MIMO) transmission, in which multiple data signals are transmitted via spatially separated PLC channels. Another scenario discussed in this thesis is the cooperative transmission between the source and destination of a PLC system by means of intermediate relay nodes in the network. Finally, the multiband transmission by utilizing different parts of the available PLC spectrum is studied. The core objective of this thesis is to develop and study novel algorithms and models to address the challenges and problems introduced in different scenarios of the multichannel PLC. These problems can be categorized as the channel selection problem for MIMO transmission, the relay selection problem for the cooperative communication, and the spectrum assignment problem for the multiband transmission. The basis of all these problems is a decision making problem, which can greatly influence the performance of the system. To address these decision making problems, a powerful mathematical tool, namely the multi-armed bandit model, is used to model the different problems emerging in different scenarios of the multichannel PLC. This modeling approach is then used as a building block for developing machine learning algorithms in order to solve the aforementioned selection problems. Finally, novel machine learning algorithms are developed and their performances are analyzed and assessed. It is shown that the machine learning approach can considerably improve the performance of the multichannel PLC systems compared to the existing state of the art approaches, by enabling the selecting agent, i.e. the PLC transmitter, to perform intelligent decisions which improves the overall performance.Die Power-Line-Communication (PLC) ist die Technologie, bei der die Datensignale eines Kommunikationssystems über die Leiter einer Energieversorgungsinfrastruktur übertragen werden. Die einzigartige Umgebung der PLC-Kanäle stellt konkrete Herausforderungen und Anforderungen dar, die modelliert und analysiert werden müssen, um ein klares Verständnis des Kommunikationssystems zu erhalten und die Fähigkeit zur Verbesserung der Leistung und Zuverlässigkeit der Übertragung zu erreichen. Darüber hinaus ist in Kommunikationssystem die Nachfrage nach erhöhtem Datendurchsatz, sowie erhöhter Zuverlässigkeit und Robustheit der Übertragung von grundlegender Bedeutung. Um diesen Herausforderungen und Anforderungen gerecht zu werden, wird in dieser Arbeit das Konzept der Mehrkanal-PLC untersucht und weiterentwickelt. Die Mehrkanal-PLC wird in diesem Zusammenhang auf die Übertragung mehrerer informationstragenden Signale über den PLC-Kanal von einer Quelle zu einem Ziel bezogen. Wir untersuchen mehrere Szenarien der Mehrkanal-Datenübertragung, um die vielfältigen Anforderungen einer PLC-Übertragung zu behandeln. Eines der in dieser Arbeit besprochenen Mehrkanal-Szenarien ist die Multiple-Input-Multiple-Output-Übertragung (MIMO), bei der mehrere Datensignale über räumlich getrennte PLC-Kanäle übertragen werden. Ein weiteres Szenario, das in dieser Arbeit diskutiert wird, ist die kooperative Übertragung zwischen der Quelle und dem Ziel eines PLC-Systems mittels Zwischenrelais als Knoten im Netzwerk. Schließlich wird die Multiband-Übertragung unter Verwendung unterschiedlicher Teile des verfügbaren PLC-Spektrums untersucht. Das Kernziel dieser Arbeit ist es, neuartige Algorithmen und Modelle zu entwickeln und zu untersuchen, um die Herausforderungen und Probleme zu lösen, die in verschiedenen Szenarien der Mehrkanal-PLC existieren. Diese Probleme sind als das Kanalauswahlproblem für die MIMO-Übertragung, das Relaiauswahlproblem für die kooperative Kommunikation und das Spektrum-Zuweisungsproblem für die Multibandübertragung kategorisiert werden. Die Basis all dieser Probleme ist ein Entscheidungsproblem, das die Leistungsfähigkeit des Systems stark beeinflussen kann. Um diese Probleme lösen zu können, wird ein mathematisches Werkzeug, nämlich das mehrarmige Bandit-Modell, verwendet, um die verschiedenen Probleme zu modellieren, die sich in verschiedenen Szenarien der Mehrkanal-PLC ergeben. Dieser Modellierungsansatz wird als Baustein für die Entwicklung von maschinellen Lernalgorithmen verwendet, um die zuvor beschriebenen Auswahlprobleme zu lösen. Schließlich werden neuartige maschinelle Lernalgorithmen entwickelt und ihre Leistungen analysiert sowie bewertet. Es zeigt sich, dass der maschinelle Lernansatz die Leistungsfähigkeit der Mehrkanal-PLC-Systeme im Vergleich zu den bestehenden Ans\"atzen des Standes der Technik erheblich verbessern kann, indem es dem Auswahlagenten, d.h. dem PLC-Sender, ermöglicht, intelligente Entscheidungen durchzuführen, die die Gesamtleistung verbessern