Browsing by Author "Kahsay, Nguse"

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    Macroeconomic Effects of Foreign Aid in Ethiopia using Dynamic Computable General Equilibrium Model
    (Addis Ababa University, 2014) Kahsay, Nguse; Ferede, Tadele (PhD)
    Macroeconomic effects of foreign aid depend on how it affects savings, investment and government behaviour. The study used recursive dynamic general equilibrium (DCGE), auto regressive distributed lag model approach to cointegration (ARDL) and vivid three gap based descriptive reports aiming to find out the preponderant effect. The data used in descrptive analysis and ARDL were collected from World Bank, Organization for Economic Cooperation and Development, and International Monetary Fund data bases. DCGE requires social accounting matrix (SAM) and that was obtained from Ethiopian Development Research Institute (EDRI). The SAM was built in 2005 and updated its key accounts in 20091. Using recursive DCGE, the study shows that aid inflow can result in export reduction and exchange rate appreciation. But, it leads to higher gevernemt revenue, expenditure and savings. Aid‟s effect in total absorption and gross domestic product is not discernible. Thus, the study‟s results are ambiguous to generalize. The long run results of the ARDL model also show significant positive relationship between national income and domestic savings. However, the relationsip between Development Assistance Committee (DAC)-aid inflow and domestic savings is significantly inverse2.1 The recursive feature of the model ensures generation of SAM in years when SAM was not actually collected. 2 A 1 unit increment in DAC-aid inflow results in 0.5 unit reduction in domestic savings.
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    Performance Analysis of Spectral Efficiency for 5G Enhanced Mobile Broadband Network with Massive MIMO
    (Addis Ababa University, 2022-01) Kahsay, Nguse; Yihenew, Wondie (PhD)
    Due to the increase of the number of users and applications, the improvement of technology is also ongoing. Wireless mobile communications need high data rate and capacity at the same time. Future generation wireless communication will have to deal with some basic requirements for serving large number users with high throughput. The fifth generation (5G) network needs to evolve in order to increase the capacity higher than the fourth generation of networks by 2025. In practice, the inter-user interference in multi-cell network has impact when more users access the wireless network and reduces performance of the system. This thesis explains the basic motivations behind Massive MIMO technology in application to 5G enhanced mobile broadband network, and provides analysis for spectral efficiency in different propagation environments. First, Lower bound SE expressions are derived to enable efficient system-level analysis under LoS and NLoS propagation environments under the assumption that channel state information is acquired by using pilot sequences (reused across the network) with densification of BSs so as to improve the SE for UEs. Simulations are used to show what happens to SE for different path loss models, BS antennas M, and different UEs K under these propagation environments. The numerical analysis shows that the SE as a function of BS density achieves its maximum for a relatively small density of BS, irrespective of the processing scheme used. This is different from distance-independent path loss model, in which the SE is a non-decreasing function of BS density. ZF processing is found to be good compensation in complexity and performance in spectral efficiency, which is then used to optimize, for a given BS density, the pilot reuse factor, number of BS antennas and UEs.