Browsing by Author "Shao, Bertha"

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    Open source cellular technologies for cost effective cellular connectivity in rural areas
    (Foundation of Computer Science, 2016) Anthony, Faustine; Gabriel, Maria; Shao, Bertha
    Cellular coverage is often a challenge in low population density and low income rural areas of the developing world like Tanzania. This is because big Telecom companies defer from deploying their expensive infrastructure in these areas fearing operations cost. It is proposed that the use of cellular open source technology as the basis for a new rural cellular network can go a long way in meeting this challenge by providing coverage in rural areas whilst simultaneously bringing down the cost of communication. This paper provides survey of recent open source cellular technologies. It further presents a prototype based on Open BTS for cellular connectivity in developing countries. In lab performance test for the proposed pro-to type confirm the feasibility of deploying cellular network based on open source technologies as an alternative to conventional mobile operator networks in a bid to solve the challenge.
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    Performance analysis of multiple access techniques for broadband power line communication system
    (Tylor & Francis, 2014) Victor, Crallet; Shao, Bertha; Mtonyole, Nixon
    Broadband over power lines is the way of providing internet services to customers using high frequency signals integrated in the power wiring. For uplink internet services data signals are modulated and coupled into the overhead power lines. For the downlink data signals are decoupled at the consumer’s premises. BPL can be a solution for people living rural area where there is electricity, since the cost of laying network cables and building the necessary infrastructure to every house is too high. BPL can serve to cut down the costs by eliminating the need for laying new infrastructure. A successful deployment of BPL requires a MAC layer that can cope with powerline channel impairments. The purpose of MAC layer is to provide a multiple access scheme, resource sharing and traffic control functions. Multiple access schemes divide up to the total signaling resource into channels and then assign these channels to different users. To achieve that the transmission medium is divided along the time, frequency and/or code axes. There are various multiple access schemes, but in this paper FDMA and TDMA are the two multiple access schemes which are taken into consideration. Their performances under different channel conditions have been found. The channel conditions considered are low, medium and high disturbances. It was found that TDMA performsbetter than FDMA under all these channel conditions
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    Performance evaluation of multiple access techniques for broadband power line communication systems
    (The University of Dodoma, 2013) Shao, Bertha
    Powerline communication (PLC) is a promising technique for information transmission using existing power lines. Broadband over power lines is the way of providing internet services to customers using high frequency signals integrated in the power wiring. The internet signals are modulated and coupled into the overhead power lines. The signals are decoupled at the consumer’s premises. BPL can be a solution for people living in any rural area where there is electricity, since the cost of laying cables and building the necessary infrastructure to every house is too high, BPL can serve to cut down the costs by eliminating the need for laying new infrastructure. A multiple access scheme of the MAC layer establishes a method of dividing the transmission resource into accessible sections. Multiple access techniques divide up to the total signaling resource into channels and then assign these channels to different users. The most common ways to divide up the transmission medium are along the time, frequency and/or code axes. In this research FDMA and TDMA are the two multiple access schemes which are taken into consideration. Their performances under different channel conditions have been found. The channel conditions considered are low, medium and high disturbances. It was found that TDMA performs better than FDMA under all these channel conditions.