Journal on Communications ›› 2021, Vol. 42 ›› Issue (4): 1-21.doi: 10.11959/j.issn.1000-436x.2021098

• Topics: Strategic Technologies to Massive Connecting for the Future Mobile Networks •     Next Articles

Random access for massive Internet of things:current status, challenges and opportunities

Pingzhi FAN, Li LI, Huan CHEN, Gaofeng CHENG, Linjie YANG, Xiaobo TANG   

  1. School of Information Science and Technology, Southwest Jiaotong University, Chengdu 611756, China
  • Revised:2021-04-08 Online:2021-04-25 Published:2021-04-01
  • Supported by:
    The National Key Research and Development Program of China(2018YFB1801104);The National Natural Science Foundation of China(62071394);Sichuan Science and Technology Program(2020YFH0011)

Abstract:

In conventional communication systems, the random access (RA) is a necessary procedure for a user equipment (UE) to establish wireless connection to the network before actual data transmission.Focusing on the massive IoT with large number of nodes, the fundamental characteristics and limitations of conventional grant-based RA were firstly discussed.Then, the grant-free RA, semi-grant-free RA and unsourced RA for massive IoT were addressed in details from multiple perspectives, including their system models, protocol frameworks, algorithm procedures, system performance, related pros and cons, as well as critical challenges and potential opportunities.Finally, some highlights on the related key techniques and common issues in random access for massive IoT were concluded.

Key words: massive Internet of things, random access, grant-free, unsourced random access, non-orthogonal multiple access

CLC Number: 

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