ZTE Communications ›› 2021, Vol. 19 ›› Issue (4): 105-110.DOI: 10.12142/ZTECOM.202104012

• Research Paper • Previous Articles     Next Articles

Truly Grant-Free Technologies and Protocols for 6G

MA Yihua1,2(), YUAN Zhifeng1,2, LI Weimin1,2, LI Zhigang1,2   

  1. 1.State Key Laboratory of Mobile Network and Mobile Multimedia Technology, Shenzhen 518055, China
    2.ZTE Corporation, Shenzhen 518057, China
  • Received:2021-04-16 Online:2021-12-25 Published:2022-01-04
  • About author:MA Yihua (yihua.ma@zte.com.cn) received the B.Eng. degree from Southeast University, China in 2015 and the M.Sc. degree from Peking University, China in 2018. Since 2018 he has been with ZTE Corporation, China. He is now a senior research engineer in the Department of Wireless Algorithm, ZTE. His main research interests include mMTC, grant-free transmissions, NOMA and cell-free massive MIMO.|YUAN Zhifeng received the M.S. degree in signal and information processing from Nanjing University of Post and Telecommunications, China in 2005. From 2004 to 2006, he was mainly engaged in FPGA/SOC ASIC design. He has been a member of the wireless technology advance research department at ZTE Corporation since 2006 and has been responsible for the research of the new multiple access group since 2012. His research interests include wireless communications, MIMO system, information theory, multiple access, error control coding, adaptive algorithms and high-speed VLSI design.|LI Weimin received the M.S. degree in communication and information system from Nanjing University of Posts and Telecommunications, China in 2010, and is currently working as a technology pre-research senior engineer at ZTE Corporation. His research interests include power control, interference control, multiple access and grant-free transmission.|LI Zhigang received the B.S. degree from Jiangsu University, China in 2016 and the M.S. degree from Harbin Institute of Technology, China in 2019, and is currently working as a technology pre-research engineer at ZTE Corporation. His current research interests include wireless communication, multiple access and grant-free transmission.


The further integration of telecommunications and industry has been considerable and is expected to bring significant benefits to society and economics in 6G. It also forms some evolution trends for next-generation communication systems, including further rises in machine-type communications (MTC), uplink-dominated systems, and decentralized structures. However, the existing access protocols are not friendly to these trends. This paper analyzes the problems of existing access protocols and provides novel access technologies to solve them. These technologies include contention-based non-orthogonal multiple access (NOMA), data features, enhanced pilot design and successive interference cancellation (SIC) of diversity. With these key enablers, truly grant-free access can be realized, and some potential modifications of protocols are then analyzed. Finally, this paper uses massive and critical scenarios in digital transformations to show the great necessity of introducing novel access technologies into future communication protocols.

Key words: decentralization, digital transformations, future access protocols, MTC, uplink