Department of Informatics and Telecommunications
Πληροφορική

2024-10-30

2024

DESPOTIDOU KALLIOPI-CHRISTINA

Γεώργιος Χ. Αλεξανδρόπουλος, Αναπληρωτής Καθηγητής, Τμήμα Πληροφορικής και Τηλεπικοινωνιών, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών

Beam Management Strategies for Wireless Communications with Reconfigurable Intelligent Surfaces

English
Greek

Beam Management Strategies for Wireless Communications with Reconfigurable Intelligent Surfaces

As the demand for high-speed, reliable, and energy-efficient wireless communications continues to escalate, driven by the proliferation of connected devices and the rollout of 5G networks, new innovative technologies are essential. Reconfigurable Intelligent Surfaces (RIS) have emerged as a promising solution to enhance wireless communications by dynamically manipulating the propagation of electromagnetic waves.
This approach offers a cost-effective, energy-efficient means to improve signal quality and coverage without relying on power-hungry transceivers and/or extensive network infrastructure.
This thesis focuses on the near-field beam management problem for RIS-assisted millimeter-wave (mmWave) multi-antenna systems. We analyze key experiments from recent studies on the topic, specifically exploring hierarchical RIS phase profile codebooks for beam control in near-field environments, which are characterized by shorter communication distances and complex propagation conditions. Such environments pose unique challenges requiring sophisticated signal alignment techniques, which RIS technology adeptly addresses by intelligently reflecting and directing signals.
Through the implementation of state-of-the-art algorithms and frameworks, this thesis evaluates the effectiveness of RIS-based beam alignment and phase-shift optimization for near-field wireless communications. Extensive simulations are conducted to assess how these techniques minimize the overhead associated with channel state information (CSI) acquisition while enhancing signal quality and the overall system performance. The results affirm that RIS, in conjunction with hierarchical codebooks, can efficiently manage beam control, leading to significant improvements in energy efficiency and signal coverage for mmWave wireless communication networks.
By thoroughly investigating and validating existing methodologies, this thesis not only contributes to the understanding of some key practical considerations of the RIS technology, but also provides valuable insights into its potential limitations and future directions. The thesis' findings emphasize the critical role of RIS in revolutionizing wireless communications, especially as society moves towards increasingly connected environments with the advent of 5G-Advanced, 6G, and the Internet of Things (IoT).

Technology - Computer science

Reconfigurable Intelligent Surfaces, Hierarchical Phase-Shift Codebooks, Multi-Antenna Systems, Channel State Information, Near-Field Propagation

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https://pergamos.lib.uoa.gr/uoa/dl/object/3421718