For near-field multiuser communications based on hybrid beamforming(HBF)architectures,high-quality effective channel estimation is required to obtain the channel state information(CSI)for the design of the digital bea...For near-field multiuser communications based on hybrid beamforming(HBF)architectures,high-quality effective channel estimation is required to obtain the channel state information(CSI)for the design of the digital beamformer.To simplify the system reconfiguration and eliminate the pilot overhead required by effective channel estimation,we consider an analog-only beamforming(AoBF)architecture in this study.AoBF is designed to maximize the sum rate,it is transformed into a problem maximizing the power transmitted to the target user equipment(UE)and meanwhile minimizing the power leaked to the other UEs.To solve this problem,we use beam focusing and beam nulling and propose two AoBF schemes based on the majorization-minimization algorithm.First,the AoBF scheme based on perfect CSI is proposed,with the focus on beamforming performance and regardless of CSI acquisition.Then,the AoBF scheme based on imperfect CSI is proposed,where low-dimensional imperfect CSI is obtained by beam sweeping based on a near-field codebook.Simulation results demonstrate that the two AoBF schemes can approach HBF schemes in terms of the sum rate and outperform HBF schemes in terms of energy efficiency.展开更多
This study investigates artificial noise aided Multiuser Multiple-Input Single-Output(MU-MISO)broadcast wiretap system designs in slow fading channel environment.We adopt a beamforming technique with artificial noise ...This study investigates artificial noise aided Multiuser Multiple-Input Single-Output(MU-MISO)broadcast wiretap system designs in slow fading channel environment.We adopt a beamforming technique with artificial noise to achieve secure multiuser communication and optimize system performance.To overcome the complexity of this model,a novel optimization scheme using semiclosed-form expressions and Monte Carlo method is employed to derive the relationship between transmission parameters and secure transmission performance.In this article,we detail the procedure of our new method,and conduct some heuristic simulation works.The simulation results reveal how power allocation ratio and information rate influence the multiuser system secure transmission probability and effective secrecy throughput of the multiuser system.We compare the multiuser system security and throughput performance with each user’s performance,which helps us to verify the security ability of our method.Our research results extend the traditional single-user artificial noise design method to multiuser scenarios,and provide ideas for solving the optimization problem of multi-user broadcast communication.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U22B2007 and 62071116)。
文摘For near-field multiuser communications based on hybrid beamforming(HBF)architectures,high-quality effective channel estimation is required to obtain the channel state information(CSI)for the design of the digital beamformer.To simplify the system reconfiguration and eliminate the pilot overhead required by effective channel estimation,we consider an analog-only beamforming(AoBF)architecture in this study.AoBF is designed to maximize the sum rate,it is transformed into a problem maximizing the power transmitted to the target user equipment(UE)and meanwhile minimizing the power leaked to the other UEs.To solve this problem,we use beam focusing and beam nulling and propose two AoBF schemes based on the majorization-minimization algorithm.First,the AoBF scheme based on perfect CSI is proposed,with the focus on beamforming performance and regardless of CSI acquisition.Then,the AoBF scheme based on imperfect CSI is proposed,where low-dimensional imperfect CSI is obtained by beam sweeping based on a near-field codebook.Simulation results demonstrate that the two AoBF schemes can approach HBF schemes in terms of the sum rate and outperform HBF schemes in terms of energy efficiency.
基金National Natural Science Foundation of China(61601425)。
文摘This study investigates artificial noise aided Multiuser Multiple-Input Single-Output(MU-MISO)broadcast wiretap system designs in slow fading channel environment.We adopt a beamforming technique with artificial noise to achieve secure multiuser communication and optimize system performance.To overcome the complexity of this model,a novel optimization scheme using semiclosed-form expressions and Monte Carlo method is employed to derive the relationship between transmission parameters and secure transmission performance.In this article,we detail the procedure of our new method,and conduct some heuristic simulation works.The simulation results reveal how power allocation ratio and information rate influence the multiuser system secure transmission probability and effective secrecy throughput of the multiuser system.We compare the multiuser system security and throughput performance with each user’s performance,which helps us to verify the security ability of our method.Our research results extend the traditional single-user artificial noise design method to multiuser scenarios,and provide ideas for solving the optimization problem of multi-user broadcast communication.
