摘要
在未来6G无线蜂窝通信网络中,基站需要为分布在各个角落的海量物联网设备提供无缝连接。受限于位置因素,很多物联网设备与基站之间的通信链路由于障碍物的阻挡变得不可靠,这对于在6G时代实现物联网万物互联是一大阻碍。为了解决该难题,分析了在6G物联网中使用智能反射表面这一新技术以增加用户信号在基站端强度的可能性。具体而言,在考虑信道估计开销的前提下,聚焦物联网设备上行通信传输功率最小化问题。一方面,在配备中小规模天线的基站系统中,提出了迭代算法以联合优化用户传输功率、智能反射表面反射系数和基站波束成形。另一方面,在配备大规模天线的基站系统中,提出了具有闭式表达式的用户传输功率、智能反射表面反射系数和基站波束成形设计以降低其应用复杂度。仿真结果验证了智能反射表面在6G物联网中增加网络连接能力的巨大潜力。
In the era of the 6 G cellular networks,the base station(BS)should be able to provide seamless connectivity for a large number of Internet of things(IoT)devices distributed in various areas.However,constrained by their locations,some IoT devices may possess unreliable communication channels to the BS due to the obstacles between them.It is a big obstacle on the roadmap towards the massively connected IoT networks in the era of 6 G.To tackle this challenge,the possibility was studied to employ the newly emerging technique of intelligent reflecting surface(IRS)for enhancing the strength of the IoT devices’signals at the BS.Specifically,the transmit power minimization problem in an uplink IoT communication system was focused on,where the overhead for channel estimation was taken into account.On one hand,for the case where the BS was equipped with a small or moderate number of antennas,an iterative algorithm was proposed to jointly optimize the user power allocation,the IRS reflecting coefficients,and the BS beamforming vectors.On the other hand,for the case where the BS had a massive number of antennas,i.e.,massive multiple-input multiple-output(MIMO),a low-complexity design of the user power allocation,the IRS reflecting coefficients,and the BS beamforming vectors was provided in a closed-form.Numerical results validate the great potential of IRS for enhancing massive connectivity in the future 6 G-assisted IoT networks.
作者
王兆瑞
刘亮
李航
崔曙光
WANG Zhaorui;LIU Liang;LI Hang;CUI Shuguang(The Hong Kong Polytechnic University,Hong Kong,China;The Chinese University of Hong Kong,Shenzhen 518172,China;Shenzhen Research Institute of Big Data,Shenzhen 518172,China)
出处
《物联网学报》
2020年第2期84-95,共12页
Chinese Journal on Internet of Things
基金
国家重点研发计划(No.2018YFB1800800)
国家自然科学基金资助项目(No.61629101)
广东省重点领域研发计划(No.2018B030338001)
珠江团队项目(No.2017ZT07X152)
关键词
智能反射表面
6G
物联网
资源优化
大规模天线技术
intelligent reflecting surface
6G
Internet of things
resource allocation
massive MIMO technology
作者简介
王兆瑞(1993−),男,山西忻州人,博士,中国香港理工大学博士后研究员,主要研究方向为5G移动通信和短包通信;通信作者:刘亮(1986−),男,辽宁沈阳人,博士,中国香港理工大学助理教授,主要研究方向为下一代蜂窝通信技术和物联网。liang-eie.liu@polyu.edu.hk;李航(1985−),男,河北承德人,博士,深圳市大数据研究院副研究员,主要研究方向为新一代无线通信网络和动态优化;崔曙光(1974−),男,河北唐山人,博士,中国香港中文大学(深圳)校长讲席教授,主要研究方向为数据驱动的大规模系统控制和5G/6G智能网络。
