ZTE Communications ›› 2021, Vol. 19 ›› Issue (4): 3-15.doi: 10.12142/ZTECOM.202104002

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A Survey on Low Complexity Detectors for OTFS Systems

ZHANG Zhengquan1,2(), LIU Heng1, WANG Qianli1, FAN Pingzhi1   

  1. 1.Key Lab of Information Coding and Transmission, Southwest Jiaotong University, Chengdu 611756, China
    2.State Key Laboratory of Integrated Services Networks, Xidian University, Xi’an 710071, China
  • Received:2021-10-18 Online:2021-12-25 Published:2022-01-04
  • About author:ZHANG Zhengquan (zhangzqswjtu@163.com) received the Ph.D. degree in information and communication engineering from Southwest Jiaotong University, China in 2019. From 2008 to 2013, he was with ZTE Corporation as a communication engineer. From 2016 to 2017, he was a guest Ph.D. student with the KTH Royal Institute of Technology, Sweden. Since 2019, he has been with the Department of Communication Engineering, School of Information Science and Technology, Southwest Jiaotong University. His research interests include B5G and 6G wireless communication technologies. He is a member of IEEE.|LIU Heng received the Ph.D. degree in information and communication engineering from Southwest Jiaotong University, China in 2013. Since 2013, he has been with the Department of Communication Engineering, School of Information Science and Technology, Southwest Jiaotong University. His research interests include next-generation wireless communications, rail transit wireless communications, machine learning and intelligent wireless communications.|WANG Qianli received the B.S. and M.S. degrees in electronic and information engineering and the Ph.D. degree from the University of Electronic Science and Technology of China in 2013, 2016 and 2021, respectively. Since 2021, he has been with the Department of Communication Engineering, School of Information Science and Technology, Southwest Jiaotong University, China. His research interests include estimation theory, array signal processing, radar sensor network, and compressed sensing.|FAN Pingzhi is currently a distinguished professor of Southwest Jiaotong University, China, and a visiting professor of Leeds University, UK (1997–). He is a recipient of the UK ORS Award (1992), the National Science Fund for Distinguished Young Scholars (1998, NSFC), IEEE VT Society Jack Neubauer Memorial Award (2018), IEEE SP Society SPL Best Paper Award (2018), IEEE WCSP 10-Year Anniversary Excellent Paper Award (2009–2019), and IEEE/CIC ICCC Best Paper Award (2020). He served as a chief scientist of the National “973” Plan Project between January 2012 and December 2016. He is an IEEE VTS Distinguished Speaker (2019–2022), a fellow of IEEE, IET, CIE and CIC. His research interests include high mobility wireless communications, massive random-access techniques, and signal design and coding.
  • Supported by:
    the NSFC Project(61871334);the open research fund of the State Key Laboratory of Integrated Services Networks, Xidian University(ISN21-15);the Fundamental Research Funds for the Central Universities, SWJTU(2682020CX79);FAN Pingzhi’s work is also supported by the NSFC project(61731017);the “111” project(111-2-14)

Abstract:

The newly emerging orthogonal time frequency space (OTFS) modulation can obtain delay-Doppler diversity gain to significantly improve the system performance in high mobility wireless communication scenarios such as vehicle-to-everything (V2X), high-speed railway and unmanned aerial vehicles (UAV), by employing inverse symplectic finite Fourier transform (ISFFT) and symplectic finite Fourier transform (SFFT). However, OTFS modulation will dramatically increase system complexity, especially at the receiver side. Thus, designing low complexity OTFS receiver is a key issue for OTFS modulation to be adopted by new-generation wireless communication systems. In this paper, we review low complexity OTFS detectors and provide some insights on future researches. We firstly present the OTFS system model and basic principles, followed by an overview of OTFS detector structures, classifications and comparative discussion. We also survey the principles of OTFS detection algorithms. Furthermore, we discuss the design of hybrid OTFS and orthogonal frequency division multiplexing (OFDM) detectors in single user and multi-user multi-waveform communication systems. Finally, we address the main challenges in designing low complexity OTFS detectors and identify some future research directions.

Key words: high mobility wireless communications, OTFS, ISFFT, SFFT, delay-Doppler diversity, iterative maximum ratio combining (MRC) detection, message passing detection