Browsing by Author "Miresa, Talile"

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    Long Distance Point-to-Point Wi-Fi Link for Connectivity in Rural Areas of Ethiopia
    (Addis Ababa University, 2005-06) Miresa, Talile; Hailemariam, Dereje (PhD)
    Internet coverage in rural areas of Ethiopia is extremely limited which, in turn, limits access to knowledge, education, health, commerce and other important services. As rural areas are characterized by low-income, highly scattered and low population density, traditional approaches for backhauling based on telephone, cellular, satellite or fiber is in general expensive, especially, in low population density and low-income regions like Ethiopia. To address this rural area network access problem, this thesis proposes Institute of Electrical and Electronics Engineers (IEEE) 802.11n-based point-point technology as a backhauling solution. The thesis shows that, with careful planning, using high gain antennas and tuning relevant medium access control (MAC) layer parameters, inexpensive, off-the-shelf Wi-Fi radios can be viable solution to rural connectivity problem. The work started by assessing limitations of IEEE 802.11-based access point in a long-distance point-to-point setup. Due to the long distance, high gain antennas are required. A pair of parabolic reflectors, originally designed for satellite TV reception with their feeders replace with that of Wi- Fi, are used. The standard IEEE802.11 MAC layer performs poorly in a long-distance step; hence, the necessary MAC layer parameters were changed to fit the long distance requirements. Before deploying the system a link budget analysis had to be conducted for selected sites to predict the performance of the system. To demonstrate the appropriateness of this solution a testbed was built and deployed in the premises of Addis Ababa Institute of Technology (AAiT) over 128 meters. The testbed is built from a pair of Dragino MS14 access points connected to parabolic reflectors of 175 centimeters diameter. Several experiments were conducted on this testbed to evaluate its performance. The measured results indicate that at 128 meters distance a maximum throughput of 32.8 Mega bits per second and received signal power of -72dB was achieved by adjusting antenna height and orientation. Another experiment was conducted using Radiomobile link simulation tool to evaluate the performance of this same system when implemented in a real rural area. The simulation result showed that with extensive link planning, the same antenna can give coverage to rural area about 30 kilometers away a city. The simulation was conducted between Bishoftu city and a rural location called Chaffee Donsa.