| 1. |
- Anatory, Justinian, et al.
(författare)
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A broadband power-line communication system design scheme for typical Tanzanian low-voltage network
- 2009
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Ingår i: IEEE Transactions on Power Delivery. - USA : IEEE. - 0885-8977 .- 1937-4208. ; 24:3, s. 1218-1224
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Tidskriftsartikel (refereegranskat)abstract
- Information and communications technologies (ICTs) are gaining importance in developing countries. Power-line network is a potential infrastructure for ICT services provision. Power-lines are highly interconnected network with stochastic variation in number of branches. Under such distributed network conditions the design of a broadband power-line communication (BPLC) system is a challenge. In this paper a case study of an actual power-line network, representative of a low-voltage BPLC channel in Dar es Salaam, Tanzania is considered. We shall investigate the performance of such a low-voltage channel that uses orthogonal frequency division multiplexing (OFDM) technique with binary phase shift keying (BPSK) modulation scheme for communication. For sensitivity analysis, three different transmitter locations were chosen and receiver points were varied to identify the possible degraded performance scenarios. Analysis show that in the frequency bands of 100 MHz, the channel delay spread for such networks is about 4 s, giving a maximum number of subchannels 4096 with 512 cyclic prefix. To improve the degraded performance scenarios, the concatenated Reed Solomon outer code with punctured convolution inner code was applied to the network. It was found that when the branches were terminated by its corresponding characteristic impedances the performance is improved by 10-20 dB compared to a corresponding uncoded system. On the contrary for a coded system when the branches were terminated either in low or higher impedances compared to branch characteristic impedances the improvement was greater than 2-15 dB. This study demonstrates that the specification proposed by IEEE-802.16 broadband wireless access working groups can be used for performance improvement of distributed low-voltage systems.
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| 2. |
- Anatory, Justinian, et al.
(författare)
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An experimental validation for broadband power-line communication (BPLC) model
- 2008
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Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 23:3, s. 1380-1383
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Tidskriftsartikel (refereegranskat)abstract
- Recently, different models have been proposed for analyzing the broadband power-line communication (BPLC) systems based on transmission-line (TL) theory. In this paper, we make an attempt to validate one such BPLC model with laboratory experiments by comparing the channel transfer functions. A good agreement between the BPLC model based on TL theory and experiments are found for channel frequencies up to about 100 MHz. This work with controlled experiments for appropriate validation could motivate the application and extension of TL theory-based BPLC models for the analysis of either indoor or low-voltage or medium-voltage channels.
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| 3. |
- Anatory, Justinian, et al.
(författare)
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Broadband power-line communications : The channel capacity analysis
- 2008
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Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 23:1, s. 164-170
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Tidskriftsartikel (refereegranskat)abstract
- The power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported a decrease in channel capacity with an increase-in the number of branches for a given channel type whether it is an indoor or low-voltage (LV) or medium-voltage (MV) channel. Those studies, however, did not provide a clear insight as to how the channel capacity is related to the number of distributed branches along the line. This paper attempts to quantify and characterize the effects of channel capacity in relation to the number of branches and with different terminal loads for a given type of channel. It is shown that for a power spectral density (PSD) between -90 dBm/Hz to - 30 dBm/Hz, the channel capacity decreases by a 20-30 Mb/s/branch, 14-24 Mb/s/branch, and a 20-25 Mb/s/branch for an MV channel, LV channel, and indoor channel, respectively. It is also shown that the channel capacity is minimum when the load impedance is terminated in characteristic impedances for any type of channel treated here. It is shown that there could be a significant loss in channel capacity if a ground return was used instead of a conventional adjacent conductor return. The analysis presented in this paper would help in designing appropriate power-line communication equipment for better and efficient data transfer.
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| 4. |
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| 5. |
- Anatory, Justinian, et al.
(författare)
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Channel Characterization for Indoor Power-Line Networks
- 2009
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Ingår i: IEEE Transactions on Power Delivery. - USA : IEEE. - 0885-8977 .- 1937-4208. ; 24:4, s. 1883-1888
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Tidskriftsartikel (refereegranskat)abstract
- Power-line networks are promising mediums by which broadband services can be offered, such as Internet services, voice over Internet protocol, digital entertainment, etc. In this paper, an analysis of delay spread, coherence bandwidth, channel capacity, and averaged delay in the frequency bands up to 100 MHz for typical indoor power-line networks are studied. Earlier studies for indoor power-line networks considered frequencies up to 30 MHz only and earlier works have shown that at these frequency bands, the data rates are generally low and are inefficient for digital entertainment in comparison with wireless local-area networks standards, such as IEEE 802.11n. In this paper, it is shown that at 100 MHz, the average channel capacity for typical indoor power-line networks can be up to 2 Gb/s and it is found that by increasing the number of branches in the link between transmitting and receiving ends, the average channel capacity decreases from 2 Gb/s to 1 Gb/s (when the number of branches was increased by four times for a power spectral density of 60 dBm/Hz). At the same time, the coherence bandwidth decreased from 209.45 kHz to 137.41 kHz, which is much better than the coherence bandwidths corresponding to 30-MHz systems. It is therefore recommended to operate the indoor power-line networks at 100-MHz bandwidths for a wide variety of broadband services.
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| 6. |
- Anatory, Justinian, et al.
(författare)
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Effects of Multipath on OFDM Systems for Indoor Broadband Power-Line Communication Networks
- 2009
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Ingår i: IEEE Transactions on Power Delivery. - USA : IEEE. - 0885-8977 .- 1937-4208. ; 24:3, s. 1190-1197
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Tidskriftsartikel (refereegranskat)abstract
- Power-line networks are an excellent infrastructure for broadband data transmission. However, various multipaths within a broadband power-line communication (BPLC) system exist due to stochastic changes in the network load impedances, branches, etc. This further affects network performance. This paper attempts to investigate the performance of indoor channels of a BPLC system that uses orthogonal frequency-division multiplexing (OFDM) techniques. It is observed that when a branch is added in the link between the sending and receiving end of an indoor channel, an average of 4-dB power loss is found. Additionally, when the terminal impedances of the branch change from the line characteristic impedance to impedance of lower values, the power loss (signal-to-noise ratio) is about 0.67 dB/Omega. On the contrary, for every increase in the terminal impedances by 100 Omega, above the line characteristic impedance, the power loss is 0.1. dB/Omega. When the line terminal impedances are close to short or open circuits, OFDM techniques show degraded performance. This situation is also observed when the number of branches increases. In this paper, it is shown that to overcome such performance degradation, the concatenated Reed-Solomon codes/interleaved Viterbi methods can be used. The observations presented in the paper could be useful for an efficient design of a BPLC system that uses OFDM techniques.
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| 7. |
- Anatory, Justinian, et al.
(författare)
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Expressions for Current/Voltage distribution in broadband power-line communication networks involving branches
- 2008
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Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 23:1, s. 188-195
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Tidskriftsartikel (refereegranskat)abstract
- Estimation of electromagnetic (EM)-field emissions from broadband power-line communication systems (BPLC) is necessary, because at its operating frequencies, the radiated emis sions from BPLC systems act as sources of interference/crosstalk to other radio-communication systems. Currently, the transmission-line (TL) system used for BPLC is complex, involving arbitrarily/irregularly distributed branched networks, arbitrary termination loads, varying line lengths, and line characteristic impedance. In order to study the electromagnetic-compatibility (EMC) issues associated with the radiated emissions of such complex BPLC networks, knowledge of current and voltage distributions along the length of the power-line channels is needed. This paper attempts to derive and present generalized expressions for either the current or voltage distribution along the line (whose TL parameters are known) between the transmitting and receiving ends for any line boundary condition and configuration based on the TL theory. The expressions presented in this paper could be beneficial for direct calculation of EM emissions from BPLC systems.
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| 8. |
- Anatory, Justinian, et al.
(författare)
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On the efficacy of using ground return in the broadband power-line communications : A transmission-line analysis
- 2008
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Ingår i: IEEE Transactions on Power Delivery. - 0885-8977 .- 1937-4208. ; 23:1, s. 132-139
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Tidskriftsartikel (refereegranskat)abstract
- The power-line infrastructure has been identified as an efficient system suitable for broadband power-line communication (BPLC) to connect and control various end users. However, the network is affected by stochastic attenuations due to the number of interconnected branches, their line lengths, associated terminal loads, etc. There is yet another parameter that could influence the above stated attenuations or distortions depending on the way the signals are allowed to return to the transmitting end. In this paper, we investigate whether a finitely conducting ground return could be used for BPLC and to investigate its performance over the conventional methods Where one of the adjacent power-line conductors is-used as signal return. This study could be helpful to those who are proposing the use of ground as a return conductor in BPLC systems. It will be shown that the use of ground return for the BPLC system is effective or better only when the ground conductivity is high (>50 mS/m). When ground conditions are poorer, attenuations increase with., making them unsuitable for BPLC. There are situafrequency tions where poor ground conditions can still be used but only the transmission-line lengths are shorter. The analysis presented here is based on transmission-line solutions both under lossless (without ground return) and lossy (with ground return) conditions and are applied to typical low-voltage and medium-voltage channels. Comparisons are also made based on the power spectral densities and channel capacities.
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| 9. |
- Anatory, Justinian, et al.
(författare)
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Performance of Underground Cables That Use OFDM Systems for Broadband Power-Line Communications
- 2009
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Ingår i: IEEE Transactions on Power Delivery. - USA : IEEE. - 0885-8977 .- 1937-4208. ; 24:4, s. 1889-1897
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Tidskriftsartikel (refereegranskat)abstract
- Power-line networks are proposed for broadband data transmission. The presence of multipaths within the broadband power-line communication (BPLC) system, due to stochastic changes in the network load impedances, branches, etc. pose a real challenge as it affects network performance. This paper attempts to investigate the performance of an orthogonal frequency-division multiplexing (OFDM)-based BPLC system that uses underground cables. It is found that when a branch is added in the link between the sending and receiving end, there is an average of 4-dB power loss. In addition, when the terminal impedances of the branches that are connected to the link between the transmitting and receiving end vary from line characteristic impedance to low-impedance values, the power loss (signal-to-noise ratio) is about 0.35 dB/Omega. On the contrary, for an increase in the terminal impedances by 100 Omega above line characteristic impedance, the power loss is 0.23 dB/Omega. When the branch terminal impedances are close to short or open circuits, OFDM techniques show degraded performance. This situation is also observed when the number of branches increases. It is shown that to overcome degraded network performance, the concatenated Reed-Solomon codes/interleaved Viterbi methods can be used, which could be used for an efficient design of the BPLC system that uses OFDM techniques.
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| 10. |
- Anatory, Justinian, et al.
(författare)
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Power-line communication channel model for interconnected networks : Part II: multiconductor system
- 2009
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Ingår i: IEEE Transactions on Power Delivery. - USA : IEEE. - 0885-8977 .- 1937-4208. ; 24:1, s. 124-128
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present an approach to determine the transfer function for multiconductor power-line networks with distributed branches and load terminations for broadband power-line communication (BPLC) applications. The applicability of the proposed channel model is verified numerically in time domain using the finite-difference-time domain (FDTD) method for the solution of transmission lines. The channel model simulation results are in excellent agreement with the corresponding FDTD results. The model therefore could be useful in the analysis and design of BPLC systems involving multiconductor power-line topology.
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