Department of Computer Science and Engineering
Permanent URI for this collection
Browse
Browsing Department of Computer Science and Engineering by Author "Anatory, Justinian"
Now showing 1 - 13 of 13
Results Per Page
Sort Options
Item Broadband Power Line Communications: Analysis of Indoor Power Line Network in Developing Countries(JKUAT, 2006) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.The effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) are presented in this paper. The power line network topology adopted here is similar to that of the system found in Tanzania. Investigation on effects of network load impedances, direct transmitter to receiver line length, branched line length and numbers of branches have been carried out. The frequency response of the power line transfer function shows that position of notches and peaks in the magnitude and phase responses are largely affected by the above network parameters particularly attenuation and dispersion. The response was also observed in the time domain. The observations made in this work could be useful in the design of high performance PLC systems for data transferItem Broadband Power Line Communications: Analysis of Indoor Power Line Network in Developing Countries(JKUAT, 2006) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.The effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) are presented in this paper. The power line network topology adopted here is similar to that of the system found in Tanzania. Investigation on effects of network load impedances, direct transmitter to receiver line length, branched line length and numbers of branches have been carried out. The frequency response of the power line transfer function shows that position of notches and peaks in the magnitude and phase responses are largely affected by the above network parameters particularly attenuation and dispersion. The response was also observed in the time domain. The observations made in this work could be useful in the design of high performance PLC systems for data transferItem Broadband Power Line Communications: The factors Influencing Wave Propagations in the Medium Voltage Lines(IEEE, 2007) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.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.Item Broadband Power-Line Communication Channel Model: Comparison between Theory and Experiments(IEEE, 2008) Anatory, Justinian; Theethayi, Nelson; Thottappillil, Rajeev; Kissaka, Mussa; Mvungi, Nerey H.Recently different models have been proposed for analyzing the BPLC systems based on transmission line (TL) theory. In this paper one such BPLC model is validated using laboratory experiments by comparing the channel transfer functions. A good agreement between the BPLC model based on TL theory and experiments is found for channel frequencies up to about 100MHzItem A Broadband Power-Line Communication System Design Scheme for Typical Tanzanian Low-Voltage Network(IEEE, 2009) Anatory, Justinian; Theethayi, Nelson; Thottappillil, Rajeev; Mvungi, Nerey H.This paper presents the influence of line length, number of branches (distributed and concentrated), and terminal impedances on the performance of a low-voltage broadband power-line communication channel. For analyses, the systems chosen are typical low-voltage power-line networks found in Tanzania. The parameters varied were the network’s load impedances, direct line length (from transmitter to receiver), branched line lengths, and number of branches. From the frequency responses of the transfer functions (ratio of the received and transmitted signal), it is seen that the position of notches and peaks in the amplitude responses are affected by the aforementioned network parameters and topology. As a result, the time-domain responses are attenuated and distorted. Time-domain responses of power-line channels under various conditions are also investigated for a given pulse input at the transmitter. The observations presented in this paper could be useful for suitable power-line communication system design.Item Broadband PowerLine Communications: Performance Analysis(World Academy of Science, Engineering and Technology, 2008) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.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 transferItem Broadband Services Provision in Powerline Communications of Developing Countries(IEEE, 2005) Anatory, Justinian; Mvungi, Nerey H.; Kissaka, MussaRecently 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.Item Determination of Maximum Data Transmission Distance in Powerline Networks in Developing Countries(EAJST, 2004) Anatory, Justinian; Mvungi, Nerey H.; Kissaka, MussaRecently, Powerline communications has been considered for providing broadband access services and as a cost effective means of connectivity to non-urban and lowly populated areas. This indicates that it is a viable technology for developing countries like Tanzania where there is adequate penetration of the powerline networks. However, the use of the network for data transmission presents a number of problems that limits achievable transmission distances (hops). This paper looks at different modulation and coding techniques to maximize transmission distanceItem Digital Terrestrial Broadcasting Technologies(World Academy of Science, Engineering and Technology, 2013) Mvungi, Nerey H.; Anatory, Justinian; Simba, FatumaDigital broadcasting has been an area of active research, development, innovation and business models development in recent years. This paper presents a survey on the characteristics of the digital terrestrial television broadcasting (DTTB) standards, and implementation status of DTTB worldwide showing the standards adopted. It is clear that only the developed countries and some in the developing ones shall be able to beat the ITU set analogue to digital broadcasting migration deadline because of the challenges that these countries faces in digitizing their terrestrial broadcasting. The challenges to keep on track the DTTB migration plan are also discussed in this paper. They include financial, technology gap, policies alignment with DTTB technology, etc. The reported performance comparisons for the different standards are also presented. The interesting part is that the results for many comparative studies depends to a large extent on the objective behind such studies, hence counter claims are common.Item The Effects of Multipath on OFDM Systems for Broadband Power-Line Communications a Case of Medium Voltage Channel(World Academy of Science, Engineering and Technology, 2009) Anatory, Justinian; Theethayi, Nelson; Mwase, Christine; Thottappillil, Rajeev; Mvungi, Nerey H.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.Item Investigation on Factors Influencing the Channel Capacity of Power line Network for BPLC Systems(IEEE, 2007) Anatory, Justinian; Theethayi, Nelson; Thottappillil, Rajeev; Mvungi, Nerey H.; Kissaka, MussaPower 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) [1- 4]. 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.Item Power Line Channel Models: Comparisons between different Modeling Adopted in BPLC Systems(Università degli Studi di Udine, 2009) Anatory, Justinian; Theethayi, Nelson; Mvungi, Nerey H.The paper compares different power channel models used for modeling power line system. The models compared are Zimmermann and Dostert, Philipps, Anatory et al and generalized TL approach. The validity of the modeling was compared with ATP-EMTP which also uses transmission line approach. It is found that for a power-line network with one branch Philipps , Anatory et al and generalized TL approach have similar results with ATP-EMTP, however Zimmermann and Dostert model indicates the same amplitude with other model but different time delay. It is observed that when the numbers of branches were increased only generalized TL approach results were comparable with ATP-EMTP results. The results in paper can read to the improvements in BPLC system design.Item Towards Affordable Broadband Communication: A Quantitative Assessment of TV White Space in Tanzania(EAI, 2017-09) Matogoro, Jabhera; Mvungi, Nerey H.; Anatory, Justinian; Karandikar, Abhay; Singh, JaspreetA quantitative assessment of TV White Space in Tanzania was conducted to assess the level of spectrum utilization as well as a key milestone towards the use of white space for affordable broadband communication. Two approaches have been used; pollution and protection viewpoints and experimental spectrum measurements based on energy detection principle. The study focused on 470 – 694 MHz UHF spectrum band which is used for digital terrestrial television in Tanzania. It was found that, more than 120 MHz is available as white space in various locations in Tanzania when pollution and protection view point was used and about 184 MHz are available as white space in Dodoma urban using experimental spectrum measurements and almost 100% of the available frequencies are not used in Dodoma rural. Both approaches revealed that there is low spectrum utilization and therefore presents a best case towards development of dynamic spectrum access technologies in Tanzania.