面向大规模物联网的随机接入:现状、挑战与机遇

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

在传统通信系统中,随机接入是终端与网络之间建立无线链路的必经过程,只有在随机接入完成之后,终端与网络之间才能正常进行数据传输。聚焦大规模节点物联网,首先阐述了大规模物联网随机接入的基本特征,分析了传统授权随机接入(RA)方法对于大规模物联网应用的局限性;然后从系统模型、协议框架、算法流程、系统性能等多个角度,讨论免授权RA、半免授权RA、无用户标识RA三大类新型大规模随机接入方法,分析各类方法优缺点,并指出面临的挑战与潜在的机遇;最后对大规模物联网随机接入涉及的关键技术与共性问题进行了总结。

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.