169,137 research outputs found
Analysis of power line communications for last-hop backhaul in small cells deployment
Publicado en: :(2019-04-05),(JosĂ© A. Cortes, Francisco J. Cañete, MatĂas Toril, Luis DĂez, Alicia GarcĂa-Mozos, "Analysis of power line communications for last-hop backhaul in small cells deployment", in Proceedings of the IEEE International Symposium on Power Line Communications and its Applications, 2019.),yEditor(IEEE)The purpose of this work is to study the feasibility of using power line communications (PLC) over outdoor public lighting networks (OPLN) for last-hop backhaul in small cell deployment. The analysis is based on actual noise measurements performed in two OPLN in the city of Málaga (Spain) and on a bottom-up channel simulator, which has been designed according to the physical characteristics and the common practices in such kind of networks. Estimations of the bit-rate achieved by PLC systems following the ITU-T Rec. G.9960 (G.hn) standard, are performed and discussed. Results indicate that PLC is a promising solution for this application.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
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Investigation into the impedance and communication requirements for the low voltage distribution line in the high frequency spectrum
Power Line Communications is long established for low data rate applications over high- voltage power lines. It is now charting new territory in high speed data transmission to the high frequency band of IMHz and upwards over the low-voltage segment below the distribution transformers.' Since the power line is designed for transmission of power instead of signal transmitting originally; it has many shortages when used as a signal communication channel. The heterogeneous structure of the power line network with numerous branches and impedance mismatcheS causing reflections and attenuations during signal transmission, and thus communication signal cannot be sent out or received completely. From this point of view, the power line impedance is a very important parameter in the design of power line communication (PLC) modem architecture, which is subject to legislations that limit the signals in the line. Variations on the impedance of the power line affect the communications channel performance. For the optimum modem design, power line impedance must be known. Power line impedance changes with time, carrier frequency, load variations, architectures and locations of the lines in city, urban, rural & industrial environment.
The objective of this study is to determine the impedance of power distribution network in a frequency range from IMHz to 30MHz. This is in line with international standard bodies including CENELEC, IEC, ITV and ETSI, which stipulates that for propagation characteristics of power line and EMC regulations, data transmission rate are evolving and . are being extended all the time to data rate up to 100 Mbps.
This thesis covers impedance measurements carried out in college buildings in Somerset, UK together with some residential houses in Somerset and London. The college buildings have both three-phase and single-phase architectures with various laboratories where loads are randomly switched on and off. An impedance analyser is used to carry out the measurements which performs a scan through a programmable frequency limits and acquires impedance parameters in the frequency domain Measurements were monitored using Microsoft Remote Desk Top client application Series of experimental measurements were carried out in the Bridgwater College and residential houses in Bridgwater and also in London.
The first part of the thesis offers detailed introduction to the topics of electricity supply networks, power line communications, modulation techniques and electromagnetic compatibility, noise and transmission line characteristics.
From the experimental results, presented in graphical format, a number of conclusions can be drawn. A wide range of impedances are observed for single phase measurements, within the range of 3 - 584 Ω for large buildings and residential houses. For three phase measurements impedances varied from 21 - 340 Ω.
The thesis concludes with a suggestion of how these measurements may be used in PLC modem design. Dynamic output-impedance PLC modems may be designed using a real-time impedance detector of the power line and the adjustable output impedance-power amplifier. Therefore, modem output impedance may be matched to the real time line impedance
Power line communication (PLC) channel measurements and characterization.
M. Sc. Eng. University of KwaZulu-Natal, Durban 2014.The potential of the power line to transport both power and communication signals simultaneously has been realized and practiced for over a century, dating back to the 1900’s. Since the key aspect of power line communications being its expansivity, its implementations were largely as a retrofit technology. This motivation of power line communication is typical for low-, medium-, and high voltage distribution networks. Beyond the “last mile” part, there’s an uprising appeal for intra-building networks currently targeted for home automation (smart homes/buildings) and in-building networking. The optimum use of the existing power line channels has been a focus area for researchers and designers, with the inherent channel hostility proving a serious drawback for high speed data communications.
The low-voltage electrical network has unpredictable noise sources, moreover it has two other main disadvantages as a communication channel. The first short coming has to do with the unknown characteristics of the power cable and topology of the network, the second arises from the time-dependent fluctuation of the impedance level of the power line as the loads are switched into and out of the power line network in an unpredictable manner. These factors determine the behaviour of the power line channel when a high frequency signal is impressed on it. This study has shown that the behaviour of indoor power line channels can be captured using a multipath based model even with limited qualitative and/or quantitative knowledge of the network topology. This model is suitable for typical indoor power line channels where knowledge of the topology is near impossible. Some of the feed parameters are obtained through measurements. With sufficient adjustment of control parameters, this model was successfully validated using sample measured channels from the numerous measurements.
Through noise measurements, this study has established that impulsive noise is the rifest in the frequency band of interest. The impulsive energy rises well above background noise, which translates to possible data “black outs”. The statistics of the components of this noise are presented. A model of sufficient simplicity is used to facilitate the qualitative description of the background noise through its power spectral density. Two descriptions are provided in terms of the worst and best case scenarios of the background noise occurrences. The model has a good macroscopic capture of the noise power spectral density, with narrow-band interference visible for the worst case noise.
Due to the multipath nature of the power line channel, this study also presents the dispersive characteristics of the power line as a communication channel. The power delay profile is used to determine parameters such as first arrival delay, mean excess delay, root mean square delay spread and maximum delay spread. The statistics of these parameters are presented. Also, the coherence bandwidth of power line channels is studied and its relationship with the rms delay spread is developed. It is in view of this work that further research in power line communication and related topics shall be inspired
State-of-the-art in Power Line Communications: from the Applications to the Medium
In recent decades, power line communication has attracted considerable
attention from the research community and industry, as well as from regulatory
and standardization bodies. In this article we provide an overview of both
narrowband and broadband systems, covering potential applications, regulatory
and standardization efforts and recent research advancements in channel
characterization, physical layer performance, medium access and higher layer
specifications and evaluations. We also identify areas of current and further
study that will enable the continued success of power line communication
technology.Comment: 19 pages, 12 figures. Accepted for publication, IEEE Journal on
Selected Areas in Communications. Special Issue on Power Line Communications
and its Integration with the Networking Ecosystem. 201
On-Body Channel Measurement Using Wireless Sensors
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works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.This post-acceptance version of the paper is essentially complete, but may differ from the official copy of record, which can be found at the following web location (subscription required to access full paper): http://dx.doi.org/10.1109/TAP.2012.219693
A predefined channel coefficients library for vehicle-to-vehicle communications
It is noticeable that most of VANETs communications tests are assessed through simulation. In a majority of simulation results, the physical layer is often affected by an apparent lack of realism. Therefore, vehicular channel model has become a critical issue in the field of intelligent transport systems (ITS). To overcome the lack of realism problem, a more robust channel model is needed to reflect the reality. This paper provides an open access, predefined channel coefficients library. The library is based on 2x2 and 4x4 Multiple – Input – Multiple – Output (MIMO) systems in V2V communications, using a spatial channel model extended SCME which will help to reduce the overall simulation time. In addition, it provides a more realistic channel model for V2V communications; considering: over ranges of speeds, distances, multipath signals, sub-path signals, different angle of arrivals, different angle departures, no line of sight and line of sight. An intensive evaluation process has taken place to validate the library and acceptance results are produced. Having an open access predefined library, enables the researcher at relevant communities to test and evaluate several complicated vehicular communications scenarios in a wider manners with less time and efforts
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