Jiayi Zhang (Beijing Jiaotong University, China); Yong Zeng (Southeast University, China)
Abstract:
Extremely large-scale multiple-input-multiple-output (XL-MIMO) is a promising technology to empower the next-generation mobile communication networks. Compared with existing 5G massive MIMO, XL-MIMO is not simply an increase of the antenna elements, but possesses new channel characteristics and faces new design challenges and opportunities, in terms of channel modelling, performance analysis, CSI acquisition, and transmission technologies. However, XL-MIMO is still in its early stage of research, and some preliminary efforts have been devoted to hardware schemes and performance analysis by taking into account new channel characteristics. To illustrate the differences and similarities among these schemes, we comprehensively review existing XL-MIMO hardware designs and channel characteristics for near-field communication and sensing in this tutorial. Then, we thoroughly discuss the research status of XL-MIMO from "channel modeling", "performance analysis", and "signal processing" perspectives. Several existing challenges are introduced and respective solutions are provided. We then propose two case studies for the hybrid propagation channel modeling and the effective degrees of freedom (EDoF) computations for practical scenarios. Using our proposed solutions, we perform numerical results to investigate the EDoF performance for the scenarios with unparallel XL-MIMO surfaces and multiple user equipment, respectively. Furthermore, we discuss a novel inter-symbol interference (ISI) mitigation technique, termed delay alignment modulation (DAM), by exploiting the extremely large spatial dimension brought by large antenna arrays and the multi-path sparsity of millimeter wave and Terahertz channels. DAM enables manipulable channel delay spread for more efficient single-carrier or multi-carrier communications and sensing. Finally, we discuss several future research directions.
Short bios:
Jiayi Zhang received the B.Sc. and Ph.D. degree from Beijing Jiaotong University, China in 2007 and 2014, respectively. Since 2016, he has been a Professor with School of Electronic and Information Engineering, Beijing Jiaotong University, China. His current research interests include cell-free massive MIMO, reconfigurable intelligent surface, and extremely large-scale massive MIMO. He was the Exemplary Editor of IEEE CL in 2021. He was the Lead Guest Editor of the special issue on "Multiple Antenna Technologies for Beyond 5G" of the IEEE JSAC. He currently serves as an Associate Editor for IEEE TCOM.
Yong Zeng is a Professor with the National Mobile Communications Research Laboratory, Southeast University, China, and also with the Purple Mountain Laboratories, Nanjing, China. He received the Bachelor of Engineering and Ph.D. degrees from Nanyang Technological University, Singapore. From 2013 to 2018, he was a Research Fellow and Senior Research Fellow at National University of Singapore. From 2018 to 2019, he was a Lecturer at the School of Electrical and Information Engineering, the University of Sydney, Australia. Prof. Zeng was listed as Highly Cited Researcher by Clarivate Analytics for four consecutive years (2019-2022). He is the recipient of the Australia Research Council (ARC) Discovery Early Career Researcher Award (DECRA), 2020 IEEE Marconi Prize Paper Award in Wireless Communications, 2018 IEEE Communications Society Asia-Pacific Outstanding Young Researcher Award, 2020 & 2017 IEEE Communications Society Heinrich Hertz Prize Paper Award, 2021 IEEE ICC Best Paper Award, and 2021 China Communications Best Paper Award. He serves as an Associated Editor for IEEE Communications Letters and IEEE Open Journal of Vehicular Technology, Leading Guest Editor for IEEE Wireless Communications on ``Integrating UAVs into 5G and Beyond'' and China Communications on ``Network-Connected UAV Communications''. He is the Symposium Chair for IEEE Globecom 2021 Track on Aerial Communications, the workshop co-chair for ICC 2018-2023 workshop on UAV communications, the tutorial speaker for IEEE Globecom 2018/2019 and ICC 2019 tutorials on UAV communications.