The concept of e-Learning is now emerging in Sub Saharan African countries like Tanzania. Due to ... more The concept of e-Learning is now emerging in Sub Saharan African countries like Tanzania. Due to economic constraints and other social and cultural factors faced by these countries, the use of Information and Communication Technology (ICT) is increasing at a very low pace. The digital divide threat has propelled the Government of Tanzania to put in place the national ICT Policy in 2003 which defines the direction of all ICT activities nationally. Among the main focused areas is the use of ICT in education, since for the development of any country, there is a need of creating knowledge based society. This paper discusses the initiatives made so far to introduce the use of ICT tools to some secondary schools using open source software in e-content development to facilitate a self-learning environment
... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Ner... more ... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Nerey H. Mvungi, and Rajeev Thottappillil, Senior Member, IEEE ... the link between points A and J. The distance between points A and J was 4 km, while all branches were 30 m long. ...
Power-line networks are widely used today for broadband data transmission. However, due to multip... more Power-line networks are widely used today for broadband data transmission. However, due to multipaths within the broadband power line communication (BPLC) systems owing to stochastic changes in the network load impedances, branches, etc., network or channel capacity performances are affected. This paper attempts to investigate the performance of typical medium voltage channels that uses Orthogonal Frequency Division Multiplexing (OFDM) techniques with Quadrature Amplitude Modulation (QAM) sub carriers. It has been observed that when the load impedances are different from line characteristic impedance channel performance decreases. Also as the number of branches in the link between the transmitter and receiver increases a loss of 4dB/branch is found in the signal to noise ratio (SNR). The information presented in the paper could be useful for an appropriate design of the BPLC systems.
ABSTRACT Power line channel is proposed as an alternative for broadband data transmission especia... more ABSTRACT Power line channel is proposed as an alternative for broadband data transmission especially in developing countries like Tanzania [1]. However the channel is affected by stochastic attenuation and deep notches which can lead to the limitation of channel capacity and achievable data rate. Various studies have characterized the channel without giving exactly the maximum performance and limitation in data transfer rate may be this is due to complexity of channel modeling being used. In this paper the channel performance of medium voltage, low voltage and indoor power line channel is presented. In the investigations orthogonal frequency division multiplexing (OFDM) with phase shift keying (PSK) as carrier modulation schemes is considered, for indoor, medium and low voltage channels with typical ten branches and also Golay coding is applied for medium voltage channel. From channels, frequency response deep notches are observed in various frequencies which can lead to reduce the achievable data rate. However, is observed that data rate up to 240Mbps is realized for a signal to noise ratio of about 50dB for indoor and low voltage channels, however for medium voltage a typical link with ten branches is affected by strong multipath and coding is required for feasible broadband data transfer.
Power line has been proposed as a solution to deliver broadband services to end users. Various st... more Power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported the decrease in channel capacity with increase in number of branches for a given channel type (indoor channel or access (low voltage) channel or medium 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 number of branches and also with different terminal loads for a given type of channel. It is shown that for power spectral density (PSD) between -90dBm/Hz to -30dBm/Hz, the channel capacity decreases by 20-30Mbps/branch, 14-24Mbps/branch and 20- 25Mbps/branch for medium voltage channel, low voltage channel and indoor channel respectively. In additional, it is 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 significant loss in channel capacity if a ground return were used instead of adjacent conductor return. The analysis presented in the paper would help in designing appropriate power line communication equipment for better and efficient data transfer.
This paper presents the influencing of load impedance, line length and branches on the performanc... more This paper presents the influencing of load impedance, line length and branches on the performance of medium voltage power line communication (PLC) network. The power line network topology adopted here is similar to that of the system in Tanzania. Different investigation with regard to network load impedances, direct line length (from transmitter to receiver), branched line length and number of branches has been investigated. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude responses are largely affected in terms of attenuation and dispersion by the above said network parameters/configuration. The observations presented in the paper could be helpful in suitable design of the PLC systems for a better data transfer and system performance.
... and Nerey H. Mvungi ... Assuming interleaving between the Viterbi decoder and the Reed-Solomo... more ... and Nerey H. Mvungi ... Assuming interleaving between the Viterbi decoder and the Reed-Solomon decoder is sufficiently long, to break up long bursts of errors out of the Viterbi decoder, the Reed Solomon symbol error probability ( ) for symbols in can be upper bounded by the ...
Abstract An underground cable power transmission system is widely used in urban low-voltage power... more Abstract An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this ...
The paper presents the effects of branches on powerline networks performance using recent develop... more The paper presents the effects of branches on powerline networks performance using recent developed model. The channels segments which have been compared are access, indoor and medium voltage channels. The comparison was done by varying different load at one of the terminals. The relationship between signal level and number of branches has been established. Quadrature amplitude modulation (QAM) is applied to the access channel model and attainable bit error rate (BER) against SNR analyzed and compared with possible transmitted power. It is observed that BER degrade as number of branches increases and SNR of about 4 dB is needed to attain the original performance without a branch
... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil... more ... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil, Senior Member, IEEE, Mussa M. Kissaka, and Nerey H. Mvungi ... A and J was 4 km, 1.2 km, and 20 m, while all corresponding branch lengths were 30, 20, and 10 m long for the MV ...
Recently, different models have been proposed for analyzing the broadband power-line communicatio... more 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
Recently it has been identified that powerline network is the promise cost effective for broadban... more Recently it has been identified that powerline network is the promise cost effective for broadband accessibility compared to competitors technology. Since, powerline channel has been designed to provide electricity, using it for broadband communication various issues have to be addressed. These include channel characterization, noise, modulation to be used, coding etc. The topology of powerline network affects the transfer characteristics of the channel. In this paper, the powerline channel problems have been modeled for utilization by broadband access. In addition different techniques such as application of modulation, and coding have been addressed and the simulation results have been discussed.
... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electr... more ... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electrical and Computer Systems Engineering University of Dar es salaam, PO ... From HT pole the cable is 50mmz, 20m long, AACSR to secondary substation (distribution transformer). ...
Power line has been proposed as a solution to deliver broadband services to end users. Various st... more Power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported the decrease in channel capacity with increase in number of branches for a given channel type (indoor channel or access (low voltage) channel or medium 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 number of branches and also with different terminal loads for a given type of channel. It is shown that for power spectral density (PSD) between -90dBm/Hz to -30dBm/Hz, the channel capacity decreases by 20-30Mbps/branch, 14-24Mbps/branch and 20- 25Mbps/branch for medium voltage channel, low voltage channel and indoor channel respectively. In additional, it is 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 significant loss in channel capacity if a ground return were used instead of adjacent conductor return. The analysis presented in the paper would help in designing appropriate power line communication equipment for better and efficient data transfer.
... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Ner... more ... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Nerey H. Mvungi, and Rajeev Thottappillil, Senior Member, IEEE ... the link between points A and J. The distance between points A and J was 4 km, while all branches were 30 m long. ...
Abstract An underground cable power transmission system is widely used in urban low-voltage power... more Abstract An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this ...
... Justinian Anatory, Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil, Senior... more ... Justinian Anatory, Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil, Senior Member, IEEE, Mussa Kissaka, and Nerey Mvungi ... 10. The length from ac is 1.2 km with all branches 20 m long concentrated at node B. All terminal loads were 50 . ...
Abstract An underground cable power transmission system is widely used in urban low-voltage power... more Abstract An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this ...
... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electr... more ... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electrical and Computer Systems Engineering University of Dar es salaam, PO ... From HT pole the cable is 50mmz, 20m long, AACSR to secondary substation (distribution transformer). ...
The concept of e-Learning is now emerging in Sub Saharan African countries like Tanzania. Due to ... more The concept of e-Learning is now emerging in Sub Saharan African countries like Tanzania. Due to economic constraints and other social and cultural factors faced by these countries, the use of Information and Communication Technology (ICT) is increasing at a very low pace. The digital divide threat has propelled the Government of Tanzania to put in place the national ICT Policy in 2003 which defines the direction of all ICT activities nationally. Among the main focused areas is the use of ICT in education, since for the development of any country, there is a need of creating knowledge based society. This paper discusses the initiatives made so far to introduce the use of ICT tools to some secondary schools using open source software in e-content development to facilitate a self-learning environment
... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Ner... more ... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Nerey H. Mvungi, and Rajeev Thottappillil, Senior Member, IEEE ... the link between points A and J. The distance between points A and J was 4 km, while all branches were 30 m long. ...
Power-line networks are widely used today for broadband data transmission. However, due to multip... more Power-line networks are widely used today for broadband data transmission. However, due to multipaths within the broadband power line communication (BPLC) systems owing to stochastic changes in the network load impedances, branches, etc., network or channel capacity performances are affected. This paper attempts to investigate the performance of typical medium voltage channels that uses Orthogonal Frequency Division Multiplexing (OFDM) techniques with Quadrature Amplitude Modulation (QAM) sub carriers. It has been observed that when the load impedances are different from line characteristic impedance channel performance decreases. Also as the number of branches in the link between the transmitter and receiver increases a loss of 4dB/branch is found in the signal to noise ratio (SNR). The information presented in the paper could be useful for an appropriate design of the BPLC systems.
ABSTRACT Power line channel is proposed as an alternative for broadband data transmission especia... more ABSTRACT Power line channel is proposed as an alternative for broadband data transmission especially in developing countries like Tanzania [1]. However the channel is affected by stochastic attenuation and deep notches which can lead to the limitation of channel capacity and achievable data rate. Various studies have characterized the channel without giving exactly the maximum performance and limitation in data transfer rate may be this is due to complexity of channel modeling being used. In this paper the channel performance of medium voltage, low voltage and indoor power line channel is presented. In the investigations orthogonal frequency division multiplexing (OFDM) with phase shift keying (PSK) as carrier modulation schemes is considered, for indoor, medium and low voltage channels with typical ten branches and also Golay coding is applied for medium voltage channel. From channels, frequency response deep notches are observed in various frequencies which can lead to reduce the achievable data rate. However, is observed that data rate up to 240Mbps is realized for a signal to noise ratio of about 50dB for indoor and low voltage channels, however for medium voltage a typical link with ten branches is affected by strong multipath and coding is required for feasible broadband data transfer.
Power line has been proposed as a solution to deliver broadband services to end users. Various st... more Power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported the decrease in channel capacity with increase in number of branches for a given channel type (indoor channel or access (low voltage) channel or medium 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 number of branches and also with different terminal loads for a given type of channel. It is shown that for power spectral density (PSD) between -90dBm/Hz to -30dBm/Hz, the channel capacity decreases by 20-30Mbps/branch, 14-24Mbps/branch and 20- 25Mbps/branch for medium voltage channel, low voltage channel and indoor channel respectively. In additional, it is 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 significant loss in channel capacity if a ground return were used instead of adjacent conductor return. The analysis presented in the paper would help in designing appropriate power line communication equipment for better and efficient data transfer.
This paper presents the influencing of load impedance, line length and branches on the performanc... more This paper presents the influencing of load impedance, line length and branches on the performance of medium voltage power line communication (PLC) network. The power line network topology adopted here is similar to that of the system in Tanzania. Different investigation with regard to network load impedances, direct line length (from transmitter to receiver), branched line length and number of branches has been investigated. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude responses are largely affected in terms of attenuation and dispersion by the above said network parameters/configuration. The observations presented in the paper could be helpful in suitable design of the PLC systems for a better data transfer and system performance.
... and Nerey H. Mvungi ... Assuming interleaving between the Viterbi decoder and the Reed-Solomo... more ... and Nerey H. Mvungi ... Assuming interleaving between the Viterbi decoder and the Reed-Solomon decoder is sufficiently long, to break up long bursts of errors out of the Viterbi decoder, the Reed Solomon symbol error probability ( ) for symbols in can be upper bounded by the ...
Abstract An underground cable power transmission system is widely used in urban low-voltage power... more Abstract An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this ...
The paper presents the effects of branches on powerline networks performance using recent develop... more The paper presents the effects of branches on powerline networks performance using recent developed model. The channels segments which have been compared are access, indoor and medium voltage channels. The comparison was done by varying different load at one of the terminals. The relationship between signal level and number of branches has been established. Quadrature amplitude modulation (QAM) is applied to the access channel model and attainable bit error rate (BER) against SNR analyzed and compared with possible transmitted power. It is observed that BER degrade as number of branches increases and SNR of about 4 dB is needed to attain the original performance without a branch
... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil... more ... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil, Senior Member, IEEE, Mussa M. Kissaka, and Nerey H. Mvungi ... A and J was 4 km, 1.2 km, and 20 m, while all corresponding branch lengths were 30, 20, and 10 m long for the MV ...
Recently, different models have been proposed for analyzing the broadband power-line communicatio... more 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
Recently it has been identified that powerline network is the promise cost effective for broadban... more Recently it has been identified that powerline network is the promise cost effective for broadband accessibility compared to competitors technology. Since, powerline channel has been designed to provide electricity, using it for broadband communication various issues have to be addressed. These include channel characterization, noise, modulation to be used, coding etc. The topology of powerline network affects the transfer characteristics of the channel. In this paper, the powerline channel problems have been modeled for utilization by broadband access. In addition different techniques such as application of modulation, and coding have been addressed and the simulation results have been discussed.
... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electr... more ... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electrical and Computer Systems Engineering University of Dar es salaam, PO ... From HT pole the cable is 50mmz, 20m long, AACSR to secondary substation (distribution transformer). ...
Power line has been proposed as a solution to deliver broadband services to end users. Various st... more Power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported the decrease in channel capacity with increase in number of branches for a given channel type (indoor channel or access (low voltage) channel or medium 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 number of branches and also with different terminal loads for a given type of channel. It is shown that for power spectral density (PSD) between -90dBm/Hz to -30dBm/Hz, the channel capacity decreases by 20-30Mbps/branch, 14-24Mbps/branch and 20- 25Mbps/branch for medium voltage channel, low voltage channel and indoor channel respectively. In additional, it is 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 significant loss in channel capacity if a ground return were used instead of adjacent conductor return. The analysis presented in the paper would help in designing appropriate power line communication equipment for better and efficient data transfer.
... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Ner... more ... Justinian Anatory, Student Member, IEEE, Nelson Theethayi, Member, IEEE, Mussa M. Kissaka,Nerey H. Mvungi, and Rajeev Thottappillil, Senior Member, IEEE ... the link between points A and J. The distance between points A and J was 4 km, while all branches were 30 m long. ...
Abstract An underground cable power transmission system is widely used in urban low-voltage power... more Abstract An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this ...
... Justinian Anatory, Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil, Senior... more ... Justinian Anatory, Member, IEEE, Nelson Theethayi, Member, IEEE, Rajeev Thottappillil, Senior Member, IEEE, Mussa Kissaka, and Nerey Mvungi ... 10. The length from ac is 1.2 km with all branches 20 m long concentrated at node B. All terminal loads were 50 . ...
Abstract An underground cable power transmission system is widely used in urban low-voltage power... more Abstract An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this ...
... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electr... more ... Anatory and Nerey .H. Mvungi Department of Computer and Systems Engineering Faculty of Electrical and Computer Systems Engineering University of Dar es salaam, PO ... From HT pole the cable is 50mmz, 20m long, AACSR to secondary substation (distribution transformer). ...
The Viterbi decoder is the most favorable solution to the problem of decoding codewords from a co... more The Viterbi decoder is the most favorable solution to the problem of decoding codewords from a convolutional encoder. Viterbi decoder performs exceptionally well when a received codewords block contains single or multiple and scattered errors in a received codewords block. However, the formation of burst errors in data transmission due to high transmission speed and the widely varying error conditions of wireless media in fading channel creates decoding challenge for such conditions which result in unbearable amount of residual errors. By using Viterbi decoders’ trellis diagrams, this paper analyses the effects of burst errors to the decoder that lead to residual errors and proposes improvement to the encoding and decoding procedures of the existing (2, 1, 2) binary convolutional encoder. The improved version facilitate effectiveness in the decoder (Viterbi algorithm) in decoding burst errors and hence reduction of residual errors in a poor channel. The proposed enhancements improve the decoder’s operational performance by 75 percent. However, the proposed modification reduces the encoder’s data transmission rate from 1/2 to 1/6.
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