RISTA Member Profile | the University of Athens

National and Kapodistrian University of Athens (NKUA), known shortly as the University of Athens and registered as Ethniko kai Kapodistriako Panepistimio Athinon in European Union’s CORDIS, was founded in 1837 and is the oldest and top-ranked University in Greece located in the capital city Athens. NKUA and in particular the Intelligent Wireless Systems and Information Processing Algorithms (NOESYS) research group led by Prof. George C. Alexandropoulos, which is a pioneering group of the Department of Informatics and Telecommunications of NKUA’s School of Science, is a member of RISTA delivering various contributions to the technology of RISs for wireless communications and applications, as well as wireless localization, sensing, and their integration. A list of NKUA’s published contributions on RISs is presented below. More information about Prof. Alexandropoulos’s and his group’s portfolio on RISs is available in www.alexandropoulos.info.

• Overviews and tutorials:

• T. Gong, P. Gavriilidis, R. Ji, C. Huang, G. C. Alexandropoulos, L. Wei, M. Debbah, H. V. Poor, and C. Yuen, “Holographic MIMO communications: Theoretical foundations, enabling technologies, and future directions,” IEEE Communications Surveys & Tutorials, to appear, 2023.

• L. Wei, C. Huang, G. C. Alexandropoulos, A. M. Elbir, Z. Yang, Z. Zhang, M. Di Renzo, M. Debbah, and C. Yuen, “Wireless communications empowered by reconfigurable intelligent surfaces: Model-based vs model-free channel estimation,” Elsevier Journal of Information and Intelligence, to appear, 2023.

• M. Jian, G. C. Alexandropoulos, E. Basar, C. Huang, R. Liu, Y. Liu, and C. Yuen, “Reconfigurable intelligent surfaces for wireless communications: Overview of hardware designs, channel models, and estimation techniques,” Intelligent and Converged Networks, vol. 3, no. 1, pp. 1–32, Mar. 2022.

• G. C. Alexandropoulos, N. Shlezinger, and P. del Hougne, “Reconfigurable intelligent surfaces for rich scattering wireless communications: Recent experiments, challenges, and opportunities,” IEEE Communications Magazine, vol. 59, no. 6, pp. 28–34, June 2021.

• C. Huang, S. Hu, G. C. Alexandropoulos, A. Zappone, C. Yuen, R. Zhang, M. Di Renzo, and M. Debbah, “Holographic MIMO surfaces for 6G wireless networks: Opportunities, challenges, and trends,” IEEE Wireless Communications, vol. 27, no. 5, pp. 118–125, October 2020. (IEEE Communications Society Fred Ellersick Prize 2023)

• G. C. Alexandropoulos, G. Lerosey, M. Debbah, and M. Fink, “Reconfigurable intelligent surfaces and metamaterials: The potential of wave propagation control for 6G wireless communications,” IEEE ComSoc TCCN Newsletter, vol. 6, no. 1, June 2020.

• RIS hardware architectures:

• J. An, C. Xu, D. W. K. Ng, G. C. Alexandropoulos, C. Huang, C. Yuen, and L. Hanzo, “Stacked intelligent metasurfaces enabling efficient holographic MIMO communications for 6G,” IEEE Journal on Selected Areas in Communications, to appear, 2023.

• B. Yang, X. Cao, C. Huang, G. C. Alexandropoulos, L. Dai, C. Yuen, M. Debbah, and H. V. Poor, “Next generation reconfigurable metasurfaces: When wave propagation control meets computing,” IEEE Wireless Communications, to appear, 2023.

• G. C. Alexandropoulos, N. Shlezinger, I. Alamzadeh, M. F. Imani, H. Zhang, and Y. C. Eldar, “Hybrid reconfigurable intelligent metasurfaces: Enabling simultaneous tunable reflections and sensing for 6G wireless communications,” IEEE Vehicular Technology Magazine, under revision, 2023.

• R. Akif Tasci, F. Kilinc, E. Basar, and G. C. Alexandropoulos, “A new RIS architecture with a single power amplifier: Energy efficiency and error performance analysis,” IEEE Access, vol. 10, pp. 44804–44815, May 2022.

• H. Zhang, N. Shlezinger, I. Alamzadeh, G. C. Alexandropoulos, M. F. Imani, and Y. C. Eldar, “Channel estimation with simultaneous reflecting and sensing reconfigurable intelligent metasurfaces,” in Proc. IEEE International Workshop on Signal Processing Advances in Wireless Communications, Lucca, Italy, 27–30 September 2021, pp. 1–6.

• I. Alamzadeh, G. C. Alexandropoulos, N. Shlezinger, and M. F. Imani, “A reconfigurable intelligent surface with integrated sensing capability,” Nature Scientific Reports, vol. 11, no. 20737, pp. 1–10, Oct. 2021.

• G. C. Alexandropoulos and E. Vlachos, “A hardware architecture for reconfigurable intelligent surfaces with minimal active elements for explicit channel estimation,” in Proc. IEEE International Conference on Acoustics, Speech, and Signal Processing, Barcelona, Spain, 4–8 May 2020, pp. 9175–9179.

• RIS phase profile design/alignment:

• K. Chen-Hu, G. C. Alexandropoulos, and A. García Armada, “Differential data-aided beam training for RIS-empowered multi-antenna communications,” IEEE Access, vol. 10, pp. 113200–113213, October 2022.

• K. Chen-Hu, G. C. Alexandropoulos, and A. García Armada, “Non-coherent modulation with random phase configurations in RIS-empowered cellular MIMO systems,” ITU Journal on Future and Evolving Technologies, vol. 3, no. 2, pp. 1–14, September 2022.

• K. Chen-Hu, G. C. Alexandropoulos, and A. G. Armada, “On the feasibility of a structured phase configuration search for RIS-assisted communications,” COST, Bologna, Italy, 8–11 February 2022.

• G. C. Alexandropoulos, V. Jamali, R. Schober, and H. V. Poor, “Near-field channel estimation for RIS-enabled millimeter wave MIMO communication systems,” IEEE Sensor Array and Multichannel Signal Processing Workshop, Trondheim, Norway, 20–23 June 2022, pp. 1–5.

• V. Jamali, G. C. Alexandropoulos, R. Schober, and H. V. Poor, “Low-to-zero-overhead IRS reconfiguration: Decoupling illumination and channel estimation,” IEEE Communications Letters, vol. 26, no. 4, pp. 932–936, Apr. 2022.

• K. Chen-Hu, G. C. Alexandropoulos, and A. García Armada, “Simultaneous RIS tuning and differential data transmission for MISO OFDM wireless systems,” in Proc. IEEE Global Communications Conference, Rio de Janeiro, Brazil, 4–8 December 2022, pp. 1–6.

• J. Yuan, M. Wen, Q. Li, E. Basar, G. C. Alexandropoulos, and G. Chen, “Receive quadrature reflecting modulation for RIS-empowered wireless communications,” IEEE Transactions on Vehicular Technology, vol. 70, no. 5, pp. 5121–5125, May 2021.

• Q. Li, M. Wen, S. Wang, G. C. Alexandropoulos, and Y.-C. Wu, “Space shift keying with reconfigurable intelligent surfaces: Phase configuration designs and performance analysis,” IEEE Open Journal of the Communications Society, vol. 2, pp. 322–333, February 2021.

• S. Lin, B. Zheng, G. C. Alexandropoulos, M. Wen, M. Di Renzo, and F. Chen, “Reconfigurable intelligent surfaces with reflection pattern modulation: Beamforming design, channel estimation, and achievable rate analysis,” IEEE Transactions on Wireless Communications, vol. 20, no. 2, pp. 741–754, February 2021.

• M. Rahal, B. Denis, K. Keykhosravi, M. F. Keskin, B. Uguen, G. C. Alexandropoulos, and H. Wymeersch, “Arbitrary beam pattern approximation via RISs with measured element responses,” in Proc. Joint European Conference on Networks and Communications & 6G Summit, Grenoble, France, 7–10 June 2022, pp. 1–6.

• RIS reflection optimization (single- and multi-user, conventional and machine learning):

• M. Rahal, B. Denis, K. Keykhosravi, M. F. Keskin, B. Uguen, G. C. Alexandropoulos, and H. Wymeersch, “Performance of RIS-aided nearfield localization under beams approximation from real hardware characterization,” EURASIP Journal on Wireless Communications and Networking, to appear, 2023.

• Q. Li, M. Wen, E. Basar, G. C. Alexandropoulos, K. J. Kim, and H. V. Poor, “Cyclic-prefixed single-carrier transmission for RIS-empowered broadband wireless systems,” IEEE Transactions on Wireless Communications, to appear, 2023.

• F. Zhu, B. Wang, Z. Yang, C. Huang, Z. Zhang, G. C. Alexandropoulos, C. Yuen, and M. Debbah, “Robust holographic mmWave beamforming by self-supervised hybrid deep learning,” European Signal Processing Conference, Helsinki, Finland, 4–8 September 2023.

• A. L. Moustakas, G. C. Alexandropoulos, and M. Debbah, “Reconfigurable intelligent surfaces and capacity optimization: A large system analysis,” IEEE Transactions on Wireless Communications, to appear, 2023.

• A. L. Moustakas, G. C. Alexandropoulos, and M. Debbah, “Capacity optimization using reconfigurable intelligent surfaces: A large system approach,” in Proc. IEEE Global Communications Conference, Madrid, Spain, 7–11 December 2021, pp. 1–6.

• J. Xu, L. You, G. C. Alexandropoulos, X. Yi, W. Wang, and X. Gao, “Near-field wideband extremely large-scale MIMO transmission with holographic metasurface antennas,” IEEE Transactions on Wireless Communications, under revision, 2023.

• S. Ghose, D. Mishra, S. P. Maity, and G. C. Alexandropoulos, “RIS reflection and placement optimization for underlay D2D communications in cognitive cellular networks,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Rhodes, Greece, 4–9 June 2023, pp. 1–5.

• Q. Li, M. Wen, E. Basar, G. C. Alexandropoulos, K. J. Kim, and H. V. Poor, “Cyclic-prefixed single-carrier transmission with reconfigurable intelligent surfaces,” in Proc. Joint European Conference on Networks and Communications & 6G Summit, Grenoble, France, 7–10 June 2022, pp. 1–6.

• G. C. Alexandropoulos, K. Stylianopoulos, C. Huang, C. Yuen, M. Bennis, and M. Debbah, “Pervasive machine learning for smart radio environments enabled by reconfigurable intelligent surfaces,” IEEE Proceedings, vol. 110, no. 9, pp. 1494–1525, September 2022.

• K. Stylianopoulos, N. Shlezinger, P. del Hougne, and G. C. Alexandropoulos, “Deep-learning-assisted configuration of reconfigurable intelligent surfaces in dynamic rich-scattering environments,” in Proc. IEEE International Conference on Acoustics, Speech, and Signal Processing, Singapore, 22–27 May 2022, pp. 1–5.

• K. Stylianopoulos, G. C. Alexandropoulos, C. Huang, C. Yuen, M. Bennis, and M. Debbah, “Deep contextual bandits for orchestrating multi-user MISO systems with multiple RISs,” in Proc. IEEE International Conference on Communications, Seoul, South Korea, 16–20 May 2022, pp. 1–6.

• Y. Cheng, W. Peng, C. Huang, G. C. Alexandropoulos, C. Yuen, and M. Debbah, “RIS-aided wireless communications: Extra degrees of freedom via rotation and location optimization,” IEEE Transactions on Wireless Communications, vol. 21, no. 8, pp. 6656–6671, August 2022.

• C. Huang, Z. Yang, G. C. Alexandropoulos, K. Xiong, L. Wei, C. Yuen, and Z. Zhang, “Hybrid beamforming for RIS-empowered multi-hop terahertz communications: A DRL-based method,” in Proc. IEEE Global Communications Conference, Taipei, Taiwan, 7–11 December 2020, pp. 1–6.

• D. Selimis, K. P. Peppas, G. C. Alexandropoulos, and F. I. Lazarakis, “On the performance analysis of RIS-empowered communications over Nakagami-m fading,” IEEE Communications Letters, vol. 25, no. 7, pp. 2191–2195, July 2021.

• C. Huang, Z. Yang, G. C. Alexandropoulos, K. Xiong, L. Wei, C. Yuen, and Z. Zhang, “Multi-hop RIS-empowered terahertz communications: A DRL-based hybrid beamforming design,” IEEE Journal on Selected Areas in Communications, vol. 39, no. 6, pp. 1663–1677, June 2021.

• S. Lin, B. Zheng, G. C. Alexandropoulos, M. Wen, F.-J. Chen, and S. Mumtaz, “Adaptive transmission protocol for reconfigurable intelligent surface-assisted OFDM,” IEEE Journal on Selected Areas in Communications, vol. 38, no. 11, pp. 2653–2665, November 2020.

• C. Huang, A. Zappone, G. C. Alexandropoulos, M. Debbah, and C. Yuen, “Reconfigurable intelligent surfaces for energy efficiency in wireless communication,” IEEE Transactions on Wireless Communications, vol. 18, no. 8, pp. 4157–4170, August 2019. (IEEE Marconi Prize Paper Award in Wireless Communications 2021)

• K. Stylianopoulos and G. C. Alexandropoulos, “Online RIS configuration learning for arbitrary large numbers of 1-bit phase resolution elements,” in Proc. IEEE International Workshop on Signal Processing Advances in Wireless Communications, Oulu, Finland, 4–6 July 2022, pp. 1–6.

• K. D. Katsanos, P. Di Lorenzo, and G. C. Alexandropoulos, “Distributed sum-rate maximization of cellular communications with multiple reconfigurable intelligent surfaces,” in Proc. IEEE International Workshop on Signal Processing Advances in Wireless Communications, Oulu, Finland, 4–6 July 2022, pp. 1–6.

• K. D. Katsanos, N. Shlezinger, M. F. Imani, and G. C. Alexandropoulos, “Wideband multi-user MIMO communications with frequency selective RISs: Element response modeling and sum-rate maximization,” in Proc. IEEE International Conference on Communications, Seoul, South Korea, 16–20 May 2022, pp. 1–6.

• K. D. Katsanos, P. Di Lorenzo, and G. C. Alexandropoulos, “Distributed sum-rate maximization of cellular communications with multiple reconfigurable intelligent surfaces,” in Proc. IEEE International Workshop on Signal Processing Advances in Wireless Communications, Oulu, Finland, 4–6 July 2022, pp. 1–6.

• L. Wang, N. Shlezinger, G. C. Alexandropoulos, H. Zhang, B. Wang, and Y. C. Eldar, “Jointly learned symbol detection and signal reflection in RIS-empowered multi-user MISO communication systems,” in Proc. IEEE Asilomar Signals, Systems and Computer Conference, Pacific Grove, USA, 31 October–3 November 2021, pp. 1–7.

• G. C. Alexandropoulos, S. Samarakoon, M. Bennis, and M. Debbah, “Phase configuration learning in wireless networks with multiple reconfigurable intelligent surfaces,” in Proc. IEEE Global Communications Conference, Taipei, Taiwan, 7–11 December 2020, pp. 1–6.

• C. Huang, G. C. Alexandropoulos, C. Yuen, and M. Debbah, “Indoor signal focusing with deep learning designed reconfigurable intelligent surfaces,” in Proc. IEEE International Workshop on Signal Processing Advances in Wireless Communications, Cannes, France, 2–5 July 2019, pp. 1–6.

• Channel modeling:

• A. Rabault, L. Le Magoarou, J. Sol, G. C. Alexandropoulos, N. Shlezinger, H. V. Poor, and P. del Hougne, “On the tacit linearity assumption in common cascaded models of RIS-parametrized wireless channels,” IEEE Transactions on Wireless Communications, under review, 2023.

• R. Faqiri, C. Saigre-Tardif, G. C. Alexandropoulos, N. Shlezinger, M. F. Imani, and P. del Hougne, “PhysFad: Physics-based end-to-end channel modeling of RIS-parametrized environments with adjustable fading,” IEEE Transactions on Wireless Communications, vol. 22, no. 1, pp. 580–595, January 2023.

• L. Wei, C. Huang, G. C. Alexandropoulos, Z. Yang, J. Yang, C. Yuen, and M. Debbah, “Channel modeling and multi-user precoding for tri-polarized holographic MIMO communications,” IEEE International Conference on Communications, Rome, Italy, 28 May–1 June 2023.

• R. Faqiri, C. Saigre-Tardif, G. C. Alexandropoulos, N. Shlezinger, M. F. Imani, and P. del Hougne, “A physics-based fading channel model for smart wireless environments enabled by reconfigurable intelligent surfaces,” in Proc. IEEE Global Communications Conference, Rio de Janeiro, Brazil, 4–8 December 2022, pp. 1–6.

• L. Wei, C. Huang, G. C. Alexandropoulos, W. E. I. Sha, C. Yuen, Z. Zhang, and M. Debbah, “Holographic MIMO surfaces for multi-user communications: Channel modeling and spectral efficiency analysis,” IEEE Journal of Selected Topics in Signal Processing, vol. 16, no. 5, pp. 1112–1124, August 2022.

• L. Wei, C. Huang, G. C. Alexandropoulos, W. E. I. Sha, Z. Zhang, M. Debbah, and C. Yuen, “Multi-user wireless communications with holographic MIMO surfaces: A convenient channel model and spectral efficiency analysis,” in Proc. Joint European Conference on Networks and Communications & 6G Summit, Grenoble, France, 7–10 June 2022, pp. 1–6.

• K. D. Katsanos, N. Shlezinger, M. F. Imani, and G. C. Alexandropoulos, “Wideband multi-user MIMO communications with frequency selective RISs: Element response modeling and sum-rate maximization,” in Proc. IEEE International Conference on Communications, Seoul, South Korea, 16–20 May 2022, pp. 1–6. 

• Localization, sensing, and ISAC:

• S. Prabhakar Chepuri, N. Shlezinger, F. Liu, G. C. Alexandropoulos, S. Buzzi, and Y. C. Eldar, “Integrated sensing and communications with reconfigurable intelligent surfaces,” IEEE Signal Processing Magazine, to appear, 2023.

• R. Ghazalian, G. C. Alexandropoulos, G. Seco-Granados, H. Wymeersch, and R. Jäntti, “Joint 3D user and 6D hybrid reconfigurable intelligent surface localization,” IEEE Transactions on Vehicular Technology, to appear, 2023.

• J. He, A. Fakhreddine, C. Vanwynsberghe, H. Wymeersch, and G. C. Alexandropoulos, “3D localization with a single partially-connected receiving RIS: Positioning error analysis and algorithmic design,” IEEE Transactions on Vehicular Technology, to appear, 2023.

• J. He, A. Fakhreddine, H. Wymeersch, and G. C. Alexandropoulos, “Compressed-sensing-based 3D localization with distributed passive reconfigurable intelligent surfaces,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Rhodes, Greece, 4–9 June 2023, pp. 1–5.

• I. Gavras, M. A. Islam, B. Smida, and G. C. Alexandropoulos, “Full duplex holographic MIMO for near-field integrated sensing and communications,” European Signal Processing Conference, Helsinki, Finland, 4–8 September 2023.

• I. Alamzadeh, G. C. Alexandropoulos, and M. F. Imani, “Intensity-only OMP-based direction estimation for hybrid reconfigurable intelligent surfaces,” IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, Portland, USA, 23–28 July 2023.

• H. Chen, H. Kim, M. Ammous, G. Seco-Granados, G. C. Alexandropoulos, S. Valaee, and H. Wymeersch, “RISs and sidelink communications in smart cities: The key to seamless localization and sensing,” IEEE Communications Magazine, to appear, 2023.

• H. Kim, H. Chen, M. F. Keskin, Y. Ge, K. Keykhosravi, G. C. Alexandropoulos, S. Kim, and H. Wymeersch, “RIS-enabled and access-point-free simultaneous radio localization and mapping,” IEEE Transactions on Wireless Communications, to appear, 2023.

• K. Keykhosravi, B. Denis, G. C. Alexandropoulos, Z. S. He, A. Albanese, V. Sciancalepore, and H. Wymeersch, “Leveraging RIS-enabled smart signal propagation for solving infeasible localization problems,” IEEE Vehicular Technology Magazine, to appear, 2023.

• H. Kim, A. Fascista, H. Chen, Y. Ge, G. C. Alexandropoulos, G. Seco-Granados, and H. Wymeersch, “RIS–aided radar sensing and object detection with single and double bounce multipath,” IEEE International Conference on Communications, Rome, Italy, 28 May–1 June 2023, pp. 1–6.

• R. Ghazalian, H. Chen, G. C. Alexandropoulos, G. Seco-Granados, H. Wymeersch, and R. Jäntti, “RIS position and orientation estimation via multi-carrier transmissions and multiple receivers,” IEEE International Conference on Communications, Rome, Italy, 28 May–1 June 2023, pp. 1–6.

• J. He, A. Fakhreddine, and G. C. Alexandropoulos, “STAR-RIS-enabled simultaneous indoor and outdoor 3D localization: Theoretical analysis and algorithmic estimation,” IET Signal Processing, vol. 17, no. 4, e12209, April 2023.

• J. He, A. Fakhreddine, and G. C. Alexandropoulos, “Joint channel and direction estimation for ground-to-UAV communications enabled by a simultaneous reflecting and sensing RIS,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Rhodes, Greece, 4–9 June 2023, pp. 1–5.

• G. C. Alexandropoulos, I. Vinieratou, and H. Wymeersch, “Localization via multiple reconfigurable intelligent surfaces equipped with single receive RF chains,” IEEE Wireless Communications Letters, vol. 11, no. 5, pp. 1072–1076, May 2022.

• J. He, A. Fakhreddine, and G. C. Alexandropoulos, “Simultaneous indoor and outdoor 3D localization with STAR-RIS-assisted millimeter wave systems,” in Proc. 6G Summit, Abu Dhabi, UAE, 3–4 November 2022.

• K. Keykhosravi, G. Seco-Granados, G. C. Alexandropoulos, and H. Wymeersch, “RIS-enabled self-localization: Leveraging controllable reflections with zero access points,” in Proc. IEEE International Conference on Communications, Seoul, South Korea, 16–20 May 2022, pp. 1–6.

• Z. Abu-Shaban, K. Keykhosravi, M. F. Keskin, G. C. Alexandropoulos, G. Seco-Granados, and H. Wymeersch, “Near-field localization with a reconfigurable intelligent surface acting as lens,” in Proc. IEEE International Conference on Communications, Montreal, Canada, 14–18 June 2021, pp. 1–6.  

• Channel estimation/tracking:

• L. Wei, C. Huang, G. C. Alexandropoulos, Z. Yang, J. Yang, W. E. I. Sha, Z. Zhang, M. Debbah, and C. Yuen, “Tri-polarized holographic MIMO surface in near-field: Channel modeling and precoding design,” IEEE Transactions on Wireless Communications, to appear, 2023.

• H. Zhang, N. Shlezinger, G. C. Alexandropoulos, A. Shultzman, I. Alamzadeh, M. F. Imani, and Y. C. Eldar, “Channel estimation with hybrid reconfigurable intelligent metasurfaces,” IEEE Transactions on Communications, vol. 71, no. 4, pp. 2441–2456, April 2023.

• L. Wei, C. Huang, Q. Guo, Z. Yang, Z. Zhang, G. C. Alexandropoulos, C. Yuen, and M. Debbah, “Joint channel estimation and signal recovery for RIS-empowered multi-user communications,” IEEE Transactions on Communications, vol. 70, no. 7, pp. 4640–4655, July 2022.

• J. Yuan, G. C. Alexandropoulos, E. Kofidis, T. L. Jensen, and E. De Carvalho, “Channel tracking for RIS-enabled multi-user SIMO systems in time-varying wireless channels,” in Proc. IEEE International Conference on Communications, Seoul, South Korea, 16–20 May 2022, pp. 1–6.

• L. Wei, C. Huang, G. C. Alexandropoulos, Z. Yang, C. Yuen, and Z. Zhang, “Joint channel estimation and signal recovery in RIS-assisted multi-user MISO communications,” in Proc. IEEE Wireless Communications and Networking Conference, Nanjing, China, 29 March–1 April 2021, pp. 1–6.

• L. Wei, C. Huang, G. C. Alexandropoulos, C. Yuen, Z. Zhang, and M. Debbah, “Channel estimation for RIS-empowered multi-user MISO wireless communications,” IEEE Transactions on Communications, vol. 69, no. 6, pp. 4144–4157, June 2021.

• S. Lin, B. Zheng, G. C. Alexandropoulos, M. Wen, F.-J. Chen, and S. Mumtaz, “Progressive channel estimation and passive beamforming for RIS-assisted OFDM systems,” in Proc. IEEE Global Communications Conference, Taipei, Taiwan, 7–11 December 2020, pp. 1–6.

• L. Wei, C. Huang, G. C. Alexandropoulos, and C. Yuen, “Parallel factor decomposition channel estimation in RIS-assisted multi-user MISO communication,” in Proc. IEEE Sensor Array and Multichannel Signal Processing Workshop, Hangzhou, China, 8–11 June 2020, pp. 1–6.

• Use cases and deployment scenarios:

• G. C. Alexandropoulos, D.-T. Phan-Huy, K. D. Katsanos, M. Crozzoli, H. Wymeersch, P. Popovski, P. Ratajczak, Y. Bénédic, M.-H. Hamon, S. Herraiz Gonzalez, P. Mursia, M. Rossanese, V. Sciancalepore, J.-B. Gros, S. Terranova, G. Gradoni, P. Di Lorenzo, M. Rahal, B. Denis, R. D’Errico, A. Clemente, and E. Calvanese Strinati, “RIS-enabled smart wireless environments: Deployment scenarios, network architecture, bandwidth and area of influence,” EURASIP Journal on Wireless Communications and Networking, to appear, 2023.

• R. Liu, G. C. Alexandropoulos, Q. Wu, M. Jian, and Y. Liu, “How can reconfigurable intelligent surfaces drive 5G-advanced wireless networks: A standardization perspective,” in Proc. IEEE/CIC International Conference on Communications in China, Foshan, China, 11–13 August 2022, pp. 1–6.

• G. C. Alexandropoulos, M. Crozzoli, D.-T. Phan-Huy, K. D. Katsanos, H. Wymeersch, P. Popovski, P. Ratajczak, Y. Bénédic, M.-H. Hamon, S. Herraiz Gonzalez, R. D’Errico, and E. Calvanese Strinati, “Smart wireless environments enabled by RISs: Deployment scenarios and two key challenges,” in Proc. Joint European Conference on Networks and Communications & 6G Summit, Grenoble, France, 7–10 June 2022, pp. 1–6.

• E. Calvanese Strinati, G. C. Alexandropoulos, H. Wymeersch, B. Denis, V. Sciancalepore, R. D’Errico, A. Clemente, D.-T. Phan-Huy, E. De Carvalho, and P. Popovski, “Reconfigurable, intelligent, and sustainable wireless environments for 6G smart connectivity,” IEEE Communications Magazine, vol. 59, no. 10, pp. 99–105, Oct. 2021.

• I. Yildirim, F. Kilinc, E. Basar, and G. C. Alexandropoulos, “Hybrid RIS-empowered reflection and decode-and-forward relaying for coverage extension,” IEEE Communications Letters, vol. 25, no. 5, pp. 1692–1696, May 2021.

• E. Calvanese Strinati, G. C. Alexandropoulos, V. Sciancalepore, M. Di Renzo, H. Wymeersch, D.-T. Phan-Huy, M. Crozzoli, R. D’Errico, E. De Carvalho, P. Popovski, P. Di Lorenzo, L. Bastianelli, M. Belouar, J. E. Mascolo, G. Gradoni, S. Phang, G. Lerosey, and B. Denis, “Wireless environment as a service enabled by reconfigurable intelligent surfaces: The RISE-6G perspective,” in Proc. Joint European Conference on Networks and Communications & 6G Summit, Porto, Portugal, 8–11 June 2021, pp. 1–6.

• M. Di Renzo, M. Debbah, D.-T. Phan-Huy, A. Zappone, M.-S. Alouini, C. Yuen, V. Sciancalepore, G. C. Alexandropoulos, J. Hoydis, H. Gacanin, J. de Rosny, A. Bounceu, G. Lerosey, and M. Fink, “Smart radio environments empowered by AI reconfigurable meta-surfaces: An idea whose time has come,” EURASIP Journal on Wireless Communications and Networking, 129, pp. 1–20, May 2019. (EURASIP Best Paper Award 2021）    

• Secrecy/security:

• G. C. Alexandropoulos, K. D. Katsanos, M. Wen, and D. B. Da Costa, “Counteracting eavesdropper attacks through reconfigurable intelligent surfaces: A new threat model and secrecy rate optimization,” IEEE Open Journal of the Communications Society, to appear, 2023.

• K. D. Katsanos and G. C. Alexandropoulos, “Spatial secrecy spectral efficiency optimization enabled by reconfigurable intelligent surfaces,” European Signal Processing Conference, Helsinki, Finland, 4–8 September 2023.

• D. Kompostiotis, D. Vordonis, V. Paliouras, and G. C. Alexandropoulos, “Secrecy rate maximization in RIS-enabled OFDM wireless communications: The circuit-based reflection model case,” IEEE International Conference on Communications, Rome, Italy, 28 May–1 June 2023, pp. 1–6.

• J. Xu, C. Yuen, C. Huang, N. Ul Hassan, G. C. Alexandropoulos, M. Di Renzo, and M. Debbah, “Reconfiguring wireless environment via intelligent surfaces for 6G: Reflection, modulation, and security,” SCIENCE CHINA Inf. Sciences, vol. 66, no. 3, 130304, February 2023.

• K. D. Katsanos and G. C. Alexandropoulos, “Safeguarding MIMO communications with reconfigurable metasurfaces and artificial noise,” in Proc. 6G Summit, Abu Dhabi, UAE, 3–4 November 2022.

• K. D. Katsanos and G. C. Alexandropoulos, “Secrecy spectral efficiency optimization in RIS-enabled MIMO communication systems,” in Proc. IEEE International Conference on Very Large Scale Integration, Patras, Greece, 3–5 October 2022, pp. 1–6.

• Other considerations/applications:

• A. Ghaneizadeh, M. Joodaki, and G. C. Alexandropoulos, “Metasurface energy harvesters: State-of-the-art and their potential for sustainable reconfigurable intelligent surfaces,” IEEE Access, under review, 2023.

• A. Masaracchia, D. V. Huynh, G. C. Alexandropoulos, B. Canberk, O. A. Dobre, and T. Q. Duong, “Towards the metaverse realization in 6G: Orchestration of RIS-enabled Smart wireless environments via digital twins,” IEEE Internet of Things Magazine, under review, 2023.

• S. Ghose, D. Mishra, S. P. Maity, and G. C. Alexandropoulos, “Jointly optimal RIS placement and power allocation for underlay D2D communications: An outage probability minimizing approach,” IEEE Transactions on Cognitive Communications and Networking, to appear, 2023.

• F. Saggese, V. Croisfelt, R. Kotaba, K. Stylianopoulos, G. C. Alexandropoulos, and P. Popovski, “A framework for control channels applied to reconfigurable intelligent surfaces,” IEEE Transactions on Wireless Communications, under review, 2023.

• K. Stylianopoulos, M. Merluzzi, P. Di Lorenzo, and G. C. Alexandropoulos, “Lyapunov-driven deep reinforcement learning for edge inference empowered by reconfigurable intelligent surfaces,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Rhodes, Greece, 4–9 June 2023, pp. 1–5.

• R. Singh, A. Kaushik, W. Shin, G. C. Alexandropoulos, M. Toka, and M. Di Renzo, “Indexed multiple access with reconfigurable intelligent surfaces: The reflection tuning potential,” IEEE Communications Magazine, under revision, 2023.

• X. Cao, B. Yang, C. Huang, G. C. Alexandropoulos, C. Yuen, Z. Han, and H. V. Poor, “Massive access of static and mobile users via reconfigurable intelligent surfaces: Protocol design and performance analysis,” IEEE Journal on Selected Areas in Communications, vol. 40, no. 4, pp. 1253–1269, Apr. 2022.

• M. Merluzzi, F. Costanzo, K. D. Katsanos, G. C. Alexandropoulos, and P. Di Lorenzo, “Power minimizing MEC offloading with probabilistic QoS constraints for RIS-empowered communication systems,” in Proc. IEEE Global Communications Conference, Rio de Janeiro, Brazil, 4–8 December 2022, pp. 1–6.

• S. Lin, B. Zheng, G. C. Alexandropoulos, M. Wen, M. Di Renzo, and F. Chen, “Joint passive beamforming and information transfer for RIS-empowered wireless communications,” in Proc. IEEE Global Communications Conference, Taipei, Taiwan, 7–11 December 2020, pp. 1–6.

–End–

The article is submitted by George C. Alexandropoulos.  RISTA keep neutral in  all released  contents, and do not provide any express or implied guarantee.  We will not be liable for anything. The final interpretation of the abover statement is vested in RISTA and this official account. This statement will be applicable to all contents.