Yongjun Xu, Chongqing University of Posts and Telecommunications, China
Yongjun Xu (Senior Member, IEEE) received the Ph.D. degree (Hons.) in communication and information system from Jilin University, Changchun, China, in 2015. He received the Outstanding Doctoral Thesis of Jilin Province in 2016. He is currently an Associate Professor with the School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing, China. From 2018 to 2019, he was a Visiting Scholar with Utah State University, Logan, UT, USA. He has authored or coauthored more than 100 papers, including the IEEE Communications Surveys & Tutorials, IEEE Transactions on Vehicular Technology, IEEE Transactions on Cognitive Communications and Networking, IEEE Transactions on Green Communications and Networking, IEEE Internet of Tings Journal, IEEE Communications Letters, IEEE Wireless Communications Letters, etc. His recent interests include heterogeneous networks, resource allocation, intelligent reflecting surface, energy harvesting, backscatter communications, mobile edge computing, UAV communications. He serves as an Associate Editor of EURASIP Journal on Wireless Communications and Networking, an Editor of Physical Communications, an Academic Editor of Digital Communications and Networks. He serves as a reviewer for IET Communications, IEEE Transactions on Wireless Communications, IEEE Transactions on Vehicular Technology, IEEE Communications Letters, IEEE Wireless Communications Letters, and China Communications. He was the Technical Program Committee member for many international conferences, such as GLOBECOM, ICC, ICCT, WCNC, ICCC, and CITS.
徐勇军(1986-)，博士，重庆邮电大学通信与信息工程学院副教授（文峰教授），硕士研究生导师，重庆市巴渝学者青年学者，文峰青年百人，重庆“双创计划”入选者，吉林省优秀博士学位论文获得者，美国犹他州立大学访问学者，重庆大学博士后，电子与信息学报青年编委，移动通信技术重点实验室核心成员，全国高校黄大年式教师团队核心成员，中国通信学会人工智能技术与应用委员会秘书组成员。主要从事5G/6G通信、反向散射通信、UAV通信、智能反射面、异构无线网络、无线携能通信、无线资源管理等方面的研究。近五年来，主持国家自然科学基金青年基金项目、重庆市自然科学基金项目等科研项目20余项，已在《IEEE Communications Surveys and Tutorials》, 《IEEE TCOM》，《IEEE TVT》,《IEEE IoT》,《IEEE TCCN》,《IEEE TGCN》,《IEEE WCL》,《IEEE CL》,《中国科学：信息科学》,《电子学报》，《通信学报》，《电子与信息学报》，ICC, WCNC, GLOBALSIP等国际期刊及主流学术会议上发表学术论文100余篇（SCI论文40余篇）中科院一区6篇(top期刊)，二区论文10篇，通信学报等A类权威期刊11篇，申请国家发明专利23项，授权7项，H-index 15，累计影响因子200以上，获得首届川渝科技学术大会优秀论文二等奖，中国电子学会自然科学三等奖，重庆市期刊学会优秀论文一等奖，《电讯技术》年度优秀审稿人，中国通信学会分支机构年度优秀工作者。担任Physical Communication、EURASIP Journal on Wireless Communications and Networking等SCI期刊编委，IEEE TSP/TWC/TVT等旗舰期刊的审稿人，GLOBECOM/ICC/ICCT/WCNC/WCSP等国际会议Chair和TPC成员。
Title: Robust Energy Efficiency Optimization for RIS-aided Heterogeneous Networks with Distortion Noises
Abstract: The energy efficiency (EE) of femtocells is always limited by the surrounding radio environments in heterogeneous networks (HetNets), such as walls and obstacles. In this paper, we propose to deploy reconfigurable intelligent surfaces (RISs) to improve the EE of femtocells. However, perfect channel state information is more difficult to obtain due to the passive characteristics of RISs and non-cooperative relationship between different tiers. Besides, the low-cost transceivers and reflecting units suffer nontrivial hardware impairments (HWIs) due to the hardware limitations of practical systems. To this end, we investigate a realistic robust beamforming design based on max-min fairness for an RIS-aided HetNet under channel uncertainties and residual HWIs. The joint optimization of transmit beamforming vectors of femto base stations (FBSs) and the phase-shift matrices of RISs is formulated as a non-convex problem to maximize the minimum EE of the femtocell subject to the constraints of the maximum transmit power of FBSs, the quality of service of users, and unit modulus phase-shift constraints of RISs. We develop an iterative block coordinate descent-based algorithm which exploits the semi-definite relaxation, the S-procedure, and the singular value decomposition method. Simulation results reveal that the proposed algorithm outperforms existing algorithms in terms of fairness, EE, and outage probability.