Max-min rate optimization for multi-user MISO-OFDM systems assisted by RIS with a wideband model  

作　　者：Yonghua QUAN Zhong TIAN Zhengchuan CHEN Min WANG Yunjian JIA 

机构地区：[1]School of Microelectronics and Communication Engineering,Chongqing University,Chongqing,400044,China [2]Shaanxi Key Laboratory of Information Communication Network and Security,Xi’an University of Posts&Telecommunications,Xi’an,710121,China [3]School of Optoelectronic Engineering,Chongqing University of Posts and Telecommunications,Chongqing,400065,China [4]Guangxi Wireless Broadband Communication and Signal Processing Key Laboratory,Guilin University of Electronic Technology,Guilin,541004,China

出　　处：《Frontiers of Information Technology & Electronic Engineering》2023年第12期1763-1775,共13页信息与电子工程前沿（英文版）

基　　金：Project supported by the Graduate Research and Innovation Foundation of Chongqing,China(No.CYB23050);the National Natural Science Foundation of China(Nos.62271092,62001074);the Fundamental Research Funds for the Central Universities,China(No.2023CDJXY-037);the China Postdoctoral Science Foundation(No.2022M710534);the Natural Science Foundation of Chongqing,China(Nos.CSTB2023NSCQMSX0933,CSTB2022NSCQMSX0327);the Open Fund of the Shaanxi Key Laboratory of Information Communication Network and Security,China(No.ICNS202201);the Opening Project of the Guangxi Wireless Broadband Communication and Signal Processing Key Laboratory,China(No.GXKL06230206)。

摘　　要：Reconfigurable intelligent surfaces(RISs)have the capability to change the wireless environment smartly Considering the attenuation of subchannels and crowding users involved in the wideband system,we introduce RISs into the multi-user multi-input single-output(MU-MISO)system with orthogonal frequency division multiplexing(OFDM)for performance enhancement.Maximizing the minimum rate of dense users in an MU-MISO-OFDM system assisted by RIS with an approximate practical model is formulated as the joint optimization problem involving subcarrier allocation,transmit precoding(TPC)matrices at the base station,and RIS passive beamforming.A coalition-game subcarrier allocation(CSA)algorithm is proposed to solve space–frequency resource allocation on subcarriers,which reforms the interference topology among dense users.Fractional programming and convex optimization method are used to optimize the TPC matrices and the RIS passive beamforming,which improves the spectral efficiency synthetically across all subchannels in the wideband system.Simulation results indicate that the CSA algorithm provides a significant gain for dense users.Besides,the proposed joint optimization method shows the considerable advantage of the RISs in the MU-MISO-OFDM system.

关 键 词：Reconfigurable intelligent surface Max-min rate Coalition-game subcarrier allocation 

分 类 号：TN92[电子电信—通信与信息系统]