In this paper,we investigate a multi-UAV aided NOMA communication system,where multiple UAV-mounted aerial base stations are employed to serve ground users in the downlink NOMA communication,and each UAV serves its as...In this paper,we investigate a multi-UAV aided NOMA communication system,where multiple UAV-mounted aerial base stations are employed to serve ground users in the downlink NOMA communication,and each UAV serves its associated users on its own bandwidth.We aim at maximizing the overall common throughput in a finite time period.Such a problem is a typical mixed integer nonlinear problem,which involves both continuous-variable and combinatorial optimizations.To efficiently solve this problem,we propose a two-layer algorithm,which separately tackles continuous-variable and combinatorial optimization.Specifically,in the inner layer given one user association scheme,subproblems of bandwidth allocation,power allocation and trajectory design are solved based on alternating optimization.In the outer layer,a small number of candidate user association schemes are generated from an initial scheme and the best solution can be determined by comparing all the candidate schemes.In particular,a clustering algorithm based on K-means is applied to produce all candidate user association schemes,the successive convex optimization technique is adopted in the power allocation subproblem and a logistic function approximation approach is employed in the trajectory design subproblem.Simulation results show that the proposed NOMA scheme outperforms three baseline schemes in downlink common throughput,including one solution proposed in an existing literature.展开更多
为了进一步降低车联网中任务时延和能耗,提出基于NOMA(Non-orthogonal multiple access)和改进蚁群算法的车联网任务卸载策略。该策略使用NOMA进行节点间通信,以车辆在RSU(Roadside service unit)服务范围内驻留时间为主要约束条件,联...为了进一步降低车联网中任务时延和能耗,提出基于NOMA(Non-orthogonal multiple access)和改进蚁群算法的车联网任务卸载策略。该策略使用NOMA进行节点间通信,以车辆在RSU(Roadside service unit)服务范围内驻留时间为主要约束条件,联合延时和能耗建立系统损耗模型,结合ε约束处理技术和混合变量蚁群算法提出改进蚁群算法求解近似最小系统损耗。仿真结果表明,所提卸载策略较传统混合变量蚁群算法收敛更快,与其他卸载策略相比系统损耗更低,系统损耗下降幅度最高可达38.05%。展开更多
This paper introduces a framework aimed at aiding the development of sixth-generation(6G)ultra-massive machine type communications(um-MTC).Precisely,the deployment of wireless power transfer(WPT)supported device-to-de...This paper introduces a framework aimed at aiding the development of sixth-generation(6G)ultra-massive machine type communications(um-MTC).Precisely,the deployment of wireless power transfer(WPT)supported device-to-device(D2D)communication occurs within multiple-input singleoutput non-orthogonal multiple access(MISONOMA)downlink networks to facilitate spectrum and energy collaboration.A pure fractional programming(PFP)algorithm is proposed to maximize the WPT-assisted device’s energy efficiency.An optimal closed-form solution for determining the time-switching coefficient of the WPT device is provided.For the robust beamforming design,the complex multi-dimension quadratic transform is applied.Moreover,the paper applies the deep deterministic policy gradient(DDPG)-based approach to directly address the problem and compares it with the proposed algorithm.Simulation outcomes highlight two key insights:1)The PFP algorithm surpasses the performance of the DRL-based algorithm when the acquired channel state information(CSI)is accurate or contains negligible errors,while the opposite is true for imperfect CSI 2)The higher energy efficiency gains can be achieved in NOMA scheme than that in Orthogonal Multiple Access(OMA)scheme.展开更多
Applying non-orthogonal multiple access(NOMA)to the mobile edge computing(MEC)network supported by unmanned aerial vehicles(UAVs)can improve spectral efficiency and achieve massive user access on the basis of solving ...Applying non-orthogonal multiple access(NOMA)to the mobile edge computing(MEC)network supported by unmanned aerial vehicles(UAVs)can improve spectral efficiency and achieve massive user access on the basis of solving computing resource constraints and coverage problems.However,the UAV-enabled network has a serious risk of information leakage on account of the openness of wireless channel.This paper considers a UAV-MEC secure network based on NOMA technology,which aims to minimize the UAV energy consumption.To achieve the purpose while meeting the security and users’latency requirements,we formulate an optimization problem that jointly optimizes the UAV trajectory and the allocation of network resources.Given that the original problem is non-convex and multivariate coupled,we proposed an effective algorithm to decouple the nonconvex problem into independent user relation coefficients and subproblems based on successive convex approximation(SCA)and block coordinate descent(BCD).The simulation results showcase the performance of our optimization scheme across various parameter settings and confirm its superiority over other benchmarks with respect to energy consumption.展开更多
Non-orthogonal multiple access(NOMA)is a promising technology for the next generation wireless communication networks.The benefits of this technology can be further enhanced through deployment in conjunction with mult...Non-orthogonal multiple access(NOMA)is a promising technology for the next generation wireless communication networks.The benefits of this technology can be further enhanced through deployment in conjunction with multiple-input multipleoutput(MIMO)systems.Antenna selection plays a critical role in MIMO–NOMA systems as it has the potential to significantly reduce the cost and complexity associated with radio frequency chains.This paper considers antenna selection for downlink MIMO–NOMA networks with multiple-antenna basestation(BS)and multiple-antenna user equipments(UEs).An iterative antenna selection scheme is developed for a two-user system,and to determine the initial power required for this selection scheme,a power estimation method is also proposed.The proposed algorithm is then extended to a general multiuser NOMA system.Numerical results demonstrate that the proposed antenna selection algorithm achieves near-optimal performance with much lower computational complexity in both two-user and multiuser scenarios.展开更多
In this paper,the application of Non-Orthogonal Multiple Access(NOMA)is investigated in a multiple-input single-output network consisting of multiple legitimate users and a potential eavesdropper.To support secure tra...In this paper,the application of Non-Orthogonal Multiple Access(NOMA)is investigated in a multiple-input single-output network consisting of multiple legitimate users and a potential eavesdropper.To support secure transmissions from legitimate users,two NOMA Secrecy Sum Rate Transmit Beam Forming(NOMA-SSR-TBF)schemes are proposed to maximise the SSR of a Base Station(BS)with sufficient and insufficient transmit power.For BS with sufficient transmit power,an artificial jamming beamforming design scheme is proposed to disrupt the potential eavesdropping without impacting the legitimate transmissions.In addition,for BS with insufficient transmit power,a modified successive interference cancellation decoding sequence is used to reduce the impact of artificial jamming on legitimate transmissions.More specifically,iterative algorithm for the successive convex approximation are provided to jointly optimise the vectors of transmit beamforming and artificial jamming.Experimental results demonstrate that the proposed NOMA-SSR-TBF schemes outperforms the existing works,such as the maximized artificial jamming power scheme,the maximized artificial jamming power scheme with artificial jamming beamforming design and maximized secrecy sum rate scheme without artificial jamming beamforming design.展开更多
基金supported by Beijing Natural Science Fund–Haidian Original Innovation Joint Fund(L232040 and L232045).
文摘In this paper,we investigate a multi-UAV aided NOMA communication system,where multiple UAV-mounted aerial base stations are employed to serve ground users in the downlink NOMA communication,and each UAV serves its associated users on its own bandwidth.We aim at maximizing the overall common throughput in a finite time period.Such a problem is a typical mixed integer nonlinear problem,which involves both continuous-variable and combinatorial optimizations.To efficiently solve this problem,we propose a two-layer algorithm,which separately tackles continuous-variable and combinatorial optimization.Specifically,in the inner layer given one user association scheme,subproblems of bandwidth allocation,power allocation and trajectory design are solved based on alternating optimization.In the outer layer,a small number of candidate user association schemes are generated from an initial scheme and the best solution can be determined by comparing all the candidate schemes.In particular,a clustering algorithm based on K-means is applied to produce all candidate user association schemes,the successive convex optimization technique is adopted in the power allocation subproblem and a logistic function approximation approach is employed in the trajectory design subproblem.Simulation results show that the proposed NOMA scheme outperforms three baseline schemes in downlink common throughput,including one solution proposed in an existing literature.
文摘为了进一步降低车联网中任务时延和能耗,提出基于NOMA(Non-orthogonal multiple access)和改进蚁群算法的车联网任务卸载策略。该策略使用NOMA进行节点间通信,以车辆在RSU(Roadside service unit)服务范围内驻留时间为主要约束条件,联合延时和能耗建立系统损耗模型,结合ε约束处理技术和混合变量蚁群算法提出改进蚁群算法求解近似最小系统损耗。仿真结果表明,所提卸载策略较传统混合变量蚁群算法收敛更快,与其他卸载策略相比系统损耗更低,系统损耗下降幅度最高可达38.05%。
文摘This paper introduces a framework aimed at aiding the development of sixth-generation(6G)ultra-massive machine type communications(um-MTC).Precisely,the deployment of wireless power transfer(WPT)supported device-to-device(D2D)communication occurs within multiple-input singleoutput non-orthogonal multiple access(MISONOMA)downlink networks to facilitate spectrum and energy collaboration.A pure fractional programming(PFP)algorithm is proposed to maximize the WPT-assisted device’s energy efficiency.An optimal closed-form solution for determining the time-switching coefficient of the WPT device is provided.For the robust beamforming design,the complex multi-dimension quadratic transform is applied.Moreover,the paper applies the deep deterministic policy gradient(DDPG)-based approach to directly address the problem and compares it with the proposed algorithm.Simulation outcomes highlight two key insights:1)The PFP algorithm surpasses the performance of the DRL-based algorithm when the acquired channel state information(CSI)is accurate or contains negligible errors,while the opposite is true for imperfect CSI 2)The higher energy efficiency gains can be achieved in NOMA scheme than that in Orthogonal Multiple Access(OMA)scheme.
基金supported in part by the National Natural Science Foundation of China under Grant 61971474in part by the National Natural Science Foundation of China under Grant 62301594+2 种基金in part by the Special Funds of the National Natural Science Foundation of China under Grant 62341112in part by the Beijing Nova Program under Grant Z201100006820121in part by the Beijing Municipal Science and Technology Project under Grant Z181100003218015.
文摘Applying non-orthogonal multiple access(NOMA)to the mobile edge computing(MEC)network supported by unmanned aerial vehicles(UAVs)can improve spectral efficiency and achieve massive user access on the basis of solving computing resource constraints and coverage problems.However,the UAV-enabled network has a serious risk of information leakage on account of the openness of wireless channel.This paper considers a UAV-MEC secure network based on NOMA technology,which aims to minimize the UAV energy consumption.To achieve the purpose while meeting the security and users’latency requirements,we formulate an optimization problem that jointly optimizes the UAV trajectory and the allocation of network resources.Given that the original problem is non-convex and multivariate coupled,we proposed an effective algorithm to decouple the nonconvex problem into independent user relation coefficients and subproblems based on successive convex approximation(SCA)and block coordinate descent(BCD).The simulation results showcase the performance of our optimization scheme across various parameter settings and confirm its superiority over other benchmarks with respect to energy consumption.
文摘Non-orthogonal multiple access(NOMA)is a promising technology for the next generation wireless communication networks.The benefits of this technology can be further enhanced through deployment in conjunction with multiple-input multipleoutput(MIMO)systems.Antenna selection plays a critical role in MIMO–NOMA systems as it has the potential to significantly reduce the cost and complexity associated with radio frequency chains.This paper considers antenna selection for downlink MIMO–NOMA networks with multiple-antenna basestation(BS)and multiple-antenna user equipments(UEs).An iterative antenna selection scheme is developed for a two-user system,and to determine the initial power required for this selection scheme,a power estimation method is also proposed.The proposed algorithm is then extended to a general multiuser NOMA system.Numerical results demonstrate that the proposed antenna selection algorithm achieves near-optimal performance with much lower computational complexity in both two-user and multiuser scenarios.
基金supported in part by the Natural Science Foundation of Fujian Province under Grant 2022J01169the Local Science and Technology Development of Fujian Province under Grant 2021L3010+3 种基金the Key Project of Science and Technology Innovation of Fujian Province under Grant 2021G02006the National Natural Science Foundation of China under Grants 61971360 and 62271420the National Natural Science Foundation of China under Grant 62071247the Urban Carbon Neutral Science and Technology Innovation Fund Project of Beijing University of Technology ($040000514122607$)。
文摘In this paper,the application of Non-Orthogonal Multiple Access(NOMA)is investigated in a multiple-input single-output network consisting of multiple legitimate users and a potential eavesdropper.To support secure transmissions from legitimate users,two NOMA Secrecy Sum Rate Transmit Beam Forming(NOMA-SSR-TBF)schemes are proposed to maximise the SSR of a Base Station(BS)with sufficient and insufficient transmit power.For BS with sufficient transmit power,an artificial jamming beamforming design scheme is proposed to disrupt the potential eavesdropping without impacting the legitimate transmissions.In addition,for BS with insufficient transmit power,a modified successive interference cancellation decoding sequence is used to reduce the impact of artificial jamming on legitimate transmissions.More specifically,iterative algorithm for the successive convex approximation are provided to jointly optimise the vectors of transmit beamforming and artificial jamming.Experimental results demonstrate that the proposed NOMA-SSR-TBF schemes outperforms the existing works,such as the maximized artificial jamming power scheme,the maximized artificial jamming power scheme with artificial jamming beamforming design and maximized secrecy sum rate scheme without artificial jamming beamforming design.
