eprintid: 10204328 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/20/43/28 datestamp: 2025-02-05 08:53:36 lastmod: 2025-02-05 08:53:36 status_changed: 2025-02-05 08:53:36 type: article metadata_visibility: show sword_depositor: 699 creators_name: Xiao, Han creators_name: Hu, Xiaoyan creators_name: Zhang, Weile creators_name: Wang, Wenjie creators_name: Wong, Kai-Kit creators_name: Yang, Kun title: Energy-Efficient STAR-RIS Enhanced UAV-Enabled MEC Networks with Bi-Directional Task Offloading ispublished: inpress divisions: UCL divisions: B04 divisions: F46 keywords: STAR-RIS; unmanned aerial vehicle (UAV); mobile edge computing (MEC); energy efficiency note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: This paper introduces a novel multi-user mobile edge computing (MEC) scheme facilitated by a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) and a unmanned aerial vehicle (UAV). Unlike existing MEC approaches, the proposed scheme enables bi-directional offloading, allowing users to concurrently offload tasks to the MEC servers located at ground base station (BS) and UAV with the support of the STAR-RIS. To evaluate the effectiveness of the proposed MEC scheme, we first formulate an optimization problem aiming at maximizing the energy efficiency of the system while ensuring the quality of service (QoS) constraints by jointly optimizing the resource allocation, user scheduling, passive beamforming of the STAR-RIS, and the UAV trajectory. A block coordinate descent (BCD) iterative algorithm designed with the Dinkelbach’s algorithm and the successive convex approximation (SCA) technique is proposed to effectively handle the formulated non-convex optimization problem characterized by significant coupling among variables. Simulation results indicate that the proposed STAR-RIS enhanced UAV-enabled MEC scheme possesses significant advantages in enhancing the system energy efficiency over other baseline schemes including the conventional RIS-aided scheme. date: 2025-01-23 date_type: published publisher: Institute of Electrical and Electronics Engineers (IEEE) official_url: https://doi.org/10.1109/twc.2025.3529252 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2357832 doi: 10.1109/TWC.2025.3529252 lyricists_name: Wong, Kai-Kit lyricists_id: KWONG98 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: IEEE Transactions on Wireless Communications issn: 1536-1276 citation: Xiao, Han; Hu, Xiaoyan; Zhang, Weile; Wang, Wenjie; Wong, Kai-Kit; Yang, Kun; (2025) Energy-Efficient STAR-RIS Enhanced UAV-Enabled MEC Networks with Bi-Directional Task Offloading. IEEE Transactions on Wireless Communications 10.1109/TWC.2025.3529252 <https://doi.org/10.1109/TWC.2025.3529252>. (In press). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10204328/1/Energy-Efficient_STAR-RIS_Enhanced_UAV-Enabled_MEC_Networks_with_Bi-Directional_Task_Offloading.pdf