Title:Spatial Domain Index Modulation for Integrated Sensing and Communications
Presenter:Istinye University, Ahmet M. Elbir, Associate Professor
Time:10:00-11:30, October 20, 2026
Location:Room 218, Block C, Pinxue Building, Qingshuihe Campus
Host:Wu Linlong,Professor
Overview:
Next generation wireless networks focus on improving spectral efficiency (SE) while reducing power consumption and hardware cost. In order to enhance the SE, index modulation (IM) has been regarded as one of the enabling technologies via the transmission of additional information bits over the transmission media such as subcarriers, antennas and spatial paths. In this presentation, we explore the usage of spatial paths and introduce spatial path IM (SPIM) for massive multiple-input multiple-output (mMIMO) systems including the scenarios of integrated sensing and communication (ISAC) and reconfigurable intelligent surfaces (RISs). Thus, the proposed framework improves the network efficiency and the coverage with the use of RIS while SPIM provides SE improvement while maintaining the sensing performance. In order to perform SPIM, we exploit the spatial diversity of the millimeter wave channel and assign the index bits to the spatial patterns of the channel between the base station and the users through RIS. We introduce a low complexity approach for the design of hybrid beamformers, which are constructed by the steering vectors corresponding to the selected spatial path indices for SPIM-mMIMO. Furthermore, we conduct a theoretical analysis on the SE of the proposed SPIM approach, and derive the SE relationship between the SPIM-based hybrid beamforming and fully digital (FD) beamforming. Via numerical simulations, we validate our theoretical results and show that the proposed SPIM approach presents an improved SE performance, even higher than that of the use of FD beamformers while using a few RF chains.
7. About the Presenter:
Ahmet M. Elbir (Senior Member, IEEE) received the B.S. degree with Honors from Firat University in 2009, and the Ph.D. degree from the Middle East Technical University (METU) in 2016, both in electrical engineering. He is currently an Associate Professor at Istinye University. He is also a Research Fellow at University of Luxembourg since 2021. In the past, he was a Research Fellow at King Abdullah University of Science and Technology (2023-2025), the University of Hertfordshire (2021-2023), a Postdoctoral Researcher at Koc University (2020-2021) and Carleton University (2022-2023). He also worked as a Senior Researcher at Duzce University (2016-2022). His research interests include array signal processing for radar systems and wireless communications, and deep learning for multi-antenna systems. He currently serves as an Associate Editor for IEEE Transactions on Signal Processing and IEEE Transactions on Aerospace and Electronic Systems and a Senior Area Editor for IEEE Signal Processing Letters. He served as an Associate Editor for IEEE Wireless Communications Letters (2023-2026), and a Lead Guest Editor for the special issues in IEEE Journal of Selected Topics in Signal Processing, IEEE Signal Processing Magazine, IEEE Wireless Communications, IEEE Communications and Standards Magazine, IEEE Transactions on Antennas and Propagation, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing and Elsevier Signal Processing. He is also the Chair of IEEE SPS Synthetic Aperture Technical Working Group (TWG), a member of IEEE SPS Sensor Array and Multichannel (SAM) Technical Committee, a member of Steering Committee for IEEE Wireless Communications Letters, and a member of IEEE AESS Integrated Sensing and Communications TWG. Dr. Elbir is the recipient of the METU Best Ph.D. thesis award (2016), the IEEE Turkey Section Research Encouragement Award (2022), the IET Radar, Sonar & Navigation Premium Award (2022) and the IEEE AESS Harry Rowe Mimno Award (2026).
