Browsing by Author "Victor, Crallet"

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    Design of an in-home multicarrier broadband power line communication system for Tanzania homes
    (The University of Dodoma, 2012) Victor, Crallet
    Indoor broadband power-line communication (BPLC) networks with different number of branches, different terminal load impedance, different line length and impulsive noise using OFDM were considered. Earlier investigations have shown that the power-line channel suffers from multipath effects along with impulsive noise. In this dissertation the OFDM system was designed based on Anatory et al model using the impulse responses of typical Tanzania indoor power-line networks. It was observed that the maximum delay spread for such networks is 2μs, making the number of sub-channels for OFDM to be 512 with a cyclic prefix of 64 at a bandwidth of 16.5MHz. Bit error rate (BER) performance of the OFDM system under multipath effects was analysed based on the simulations of the four Tanzania indoor power-line networks at different load impedances with number of branches and branch length dictated by a particular home power-line network. It was observed that the performance of the OFDM system is affected by number of branches and load impedances. To maintain the bit error performance an average SNR per bit gain of 28dB is needed so that sustained communication is still available in all the four Tanzania indoor power-line networks. The OFDM system performance at the fixed load impedance within the same house was different indicating that the number of branches has the influence on the performance.
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    Design of multicarrier broadband power line communication system for Tanzania homes
    (Foundation of Computer Science, 2014) Victor, Crallet; Mtonyole, Nixon
    Broadband Power Line Communication (BPLC) is a method of providing broadband internet access to consumers using High Frequency (HF) radio signals coupled into the mains power wiring. In the BPLC system, data signals are modulated at HF and injected into the power lines using broadband modulation techniques. Design of a BPLC system requires a complete understanding of the Power line network (PLN) topologies involved. PLN can be classified as Indoor or In-home, Low voltage, Medium voltage and High voltage respectively. In this study four maps representing typical Tanzania houses were selected randomly, and then four indoor power-line networks were derived from their circuit diagrams. The Impulse response was estimated at the switch sockets using the recent power-line channel model by Anatory et al. The delay spread estimated from the impulse response was used to design the OFDM system and the OFDM system performance was evaluated.
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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