eprintid: 10189914 rev_number: 6 eprint_status: archive userid: 699 dir: disk0/10/18/99/14 datestamp: 2024-04-04 15:11:47 lastmod: 2024-04-04 15:11:47 status_changed: 2024-04-04 15:11:47 type: proceedings_section metadata_visibility: show sword_depositor: 699 creators_name: Sun, Y creators_name: An, K creators_name: Lin, Z creators_name: Zhu, Y creators_name: Al-Dhahir, N creators_name: Wong, KK title: Scalable Robust Beamforming for Multi-Layer Refracting RIS-Assisted HAP-SWIPT Networks ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F46 keywords: Fading channels , Wireless communication , Transmitters , Receivers , Reconfigurable intelligent surfaces , Optimization , Simultaneous wireless information and power transfer note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: To mitigate the severe large-scale fading and the energy scarcity problem in long-distance high-altitude platform (HAP) networks, in this paper, we investigate the potentials of a multi-layer refracting reconfigurable intelligent surface (RIS) -assisted receiver for enabling simultaneous wireless information and power transfer (SWIPT) in HAP networks. Unlike the existing RIS-aided reflector and transmitter, the multi-layer RIS-receiver can well overcome the severe 'double fading' effect induced by the extreme long-distance HAP links and fully exploit RIS's degrees-of-freedom (DoFs) for SWIPT design. Building on the proposed RIS-receiver, this paper formulates a worst-case sum rate maximization problem under angular channel state information (CSI) imperfection, while satisfying the information rate requirements of the earth stations (ESs) and the harvested energy constraint. To handle the intractable non-convex problem, a scalable robust optimization framework utilizing the discretization method, LogSumExp-dual scheme, and modified cyclic coordinate descent (M-CCD) is proposed to obtain the semi-closed-form solutions. Numerical simulations demonstrate that the proposed architecture and optimization framework achieve superior performance with lower complexity compared with state-of-the-art schemes in HAP networks. date: 2024-02-26 date_type: published publisher: IEEE official_url: http://dx.doi.org/10.1109/globecom54140.2023.10437169 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2262291 doi: 10.1109/GLOBECOM54140.2023.10437169 lyricists_name: Wong, Kai-Kit lyricists_id: KWONG98 actors_name: Wong, Kai-Kit actors_id: KWONG98 actors_role: owner full_text_status: public pres_type: paper publication: Proceedings - IEEE Global Communications Conference, GLOBECOM pagerange: 1656-1662 event_title: GLOBECOM 2023 - 2023 IEEE Global Communications Conference event_dates: 4 Dec 2023 - 8 Dec 2023 book_title: Proceedings - IEEE Global Communications Conference, GLOBECOM citation: Sun, Y; An, K; Lin, Z; Zhu, Y; Al-Dhahir, N; Wong, KK; (2024) Scalable Robust Beamforming for Multi-Layer Refracting RIS-Assisted HAP-SWIPT Networks. In: Proceedings - IEEE Global Communications Conference, GLOBECOM. (pp. pp. 1656-1662). IEEE Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10189914/1/a275-sun%20final.pdf