03. Bachelor's Thesis

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https://nur.nu.edu.kz/handle/123456789/8137

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Browsing 03. Bachelor's Thesis by Subject "5G"

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    BUTLER MATRIX MINIATURIZATION FOR 5G COMMUNICATIONS AND BEYOND
    (Nazarbayev University School of Engineering and Digital Sciences, 2024-04-19) Amangeldi, Yerassyl
    This capstone project presents a miniaturized implementation of Butler’s beamforming array on microstrip technology. Firstly, the basis of size reduction is obtained by developing a structure that behaves exactly as the quarter-wave transmission line segment at the operation frequency. Secondly, this structure is applied to reduce the area of higher-order components such as 3dB hybrid coupler and crossover. Then, the components are assembled into the layout of Butler Matrix where several components are reduced in size further. The obtained final structure takes up approximately two times less area at the cost of 20% theoretical bandwidth reduction. A 4-by-4 experimental setup is developed for validation at 2.5 GHz which corresponds to the lower 5G frequency band.
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    PHYSICAL LAYER SECURITY USING MASSIVE MIMO AND RIS TECHNOLOGY
    (Nazarbayev University School of Engineering and Digital Sciences, 2024-04-19) Abdrakhmanov, Rakhat
    Massive Multiple-Input-Multiple-Output (MIMO) systems and Reconfigurable Intellegent Surfaces (RIS) are considered to be the key technologies for next generations wireless communication, which are aimed to achieve higher data rates, massive connectivity and more secure data transmission. Combined use of these technologies together with artificial noise (AN) gives high hopes for strengthening Physical Layer Security (PLS) in wireless networks. This capstone work considers configuring phase shifts of RIS such that the impact of AN is maximized for illegitimate user, while its impact on legitimate user is not significant compared to the actual signal received from base station. In the proposed system model, some antennas is dedicated for AN and the rest are transmitting the actual data. The main objective of this model is to maximize Secrecy Capacity (SC) of the communication link, while satisfying the users’ quality of service (QoS). To achieve that, we optimize the phase shifts of RIS and find the optimal number of base station antennas transmitting AN. Obtained results validate theoretical concepts and show that proposed RIS-assisted Massive MIMO incorporated with AN transmission can be an effecting tool for establishing and improving PLS in wireless communication.