ZEDKA, R. Prostorová diverzita a časově-kmitočtová ortogonalita pro robustní bezdrátové komunikace [online]. Brno: Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií. 2024.
I am pleased to provide an assessment for Radim Zedka, who has submitted an outstanding dissertation titled "Spatial Diversity and Time-Frequency Orthogonality for Robust Wireless Communications." His work was also supervised by Prof. Roman Maršálek from Brno University of Technology and Dr. Marek Bobula from RACOM. Radim's dissertation is a testament to his exceptional capabilities and dedication to his field. From the onset of his studies, Radim has demonstrated remarkable academic skills and a profound understanding of his research topic. His dissertation addresses critical aspects of wireless communications, focusing on innovative techniques for enhancing robustness and efficiency. Specifically, Radim's work on space-time line codes (STLCs) and orthogonal-time-frequency-space (OTFS) systems represents significant advancements in the field. Radim's dissertation is divided into two main parts, each contributing valuable insights into robust wireless communications. The first part of his work focusses to spatial diversity techniques, particularly the development and theoretical analysis of a novel quasi-orthogonal STLC structure. This innovation allows for the utilization of four receiver antennas, doubling the capacity compared to traditional methods while maintaining full-rate transmission. His rigorous theoretical analysis of the diversity gain and asymptotic signal-to-noise ratio (SNR) gain sets a new benchmark in the field. The second part of Radim's dissertation introduces a new OTFS-based system, termed unique-word OTFS (UW-OTFS). This system considers power spectral density (PSD) as a key design parameter, a novel approach that enhances both bit-error-ratio (BER) and spectral efficiency. His comprehensive theoretical and numerical analyses, including Monte Carlo simulations, demonstrate the system's superior performance in fractional-Doppler channels. Radim has shown exceptional independence throughout his research. His ability to work autonomously is evident from his numerous collaborations and publications, reflecting a high level of initiative and scholarly engagement. The thesis not only showcases his deep technical knowledge and innovative thinking but also promises to have a significant impact on the scientific community. I would like to extend my sincere gratitude to Prof. Roman Maršálek and Dr. Marek Bobula for their invaluable guidance and support in supervising Radim's research. Their expertise and mentorship have been instrumental in the successful completion of this dissertation. In conclusion, Radim Zedka is an extraordinary student whose dissertation reflects his exceptional capabilities and dedication. His work is a significant contribution to the field of wireless communications, and I have no doubt that he will continue to make impactful advancements in his future endeavors. It has been a privilege to supervise such a talented and diligent researcher.
viz pdf
viz pdf
eVSKP id 160745