针对无人机基站空对地通信链路易受窃听攻击的问题,提出一种基于隐蔽信息映射的广义空间方向调制系统(covert information mapped-generalized spatial and direction modulation,CIM-GSDM),将信息隐藏于激活接收机子集的索引及其选择...针对无人机基站空对地通信链路易受窃听攻击的问题,提出一种基于隐蔽信息映射的广义空间方向调制系统(covert information mapped-generalized spatial and direction modulation,CIM-GSDM),将信息隐藏于激活接收机子集的索引及其选择组合中,引入与合法方信道正交的人工噪声干扰窃听方。为进一步提升系统的传输安全性,研究提出了预编码矩阵和功率分配因子联合优化框架,通过有效管理多波束传输和人工噪声的功率分配,增强系统安全性。首先,推导基于系统安全速率的物理层安全性指标,以此为优化目标,联合优化预编码矩阵和人工噪声功率分配因子。为解决该非凸的联合优化问题,考虑交替优化2个变量,提出基于Nesterov下降的自然梯度下降法,通过快速迭代更新预编码矩阵,解决CIM-GSDM符号候选集规模较大带来的计算复杂度问题。基于合法方信噪比与窃听方干信噪比的乘积最大化准则,推导出功率分配因子的次优闭式解。仿真结果表明,所提优化算法在保证合法方可达到的速率前提下,显著降低窃听方的窃听速率,有效保证CIM-GSDM系统的传输安全性。相比传统波束成形算法及固定功率分配因子的方法,提出算法在安全性能上具有显著优势。展开更多
The simultaneous transmitting and reflecting reconfigurable intelligent surface(STAR-RIS)can independently adjust surface’s reflection and transmission coefficients so as to enhance space coverage.For a multiple-inpu...The simultaneous transmitting and reflecting reconfigurable intelligent surface(STAR-RIS)can independently adjust surface’s reflection and transmission coefficients so as to enhance space coverage.For a multiple-input multiple-output(MIMO)communication system with a STAR-RIS,a base station(BS),an eavesdropper,and multiple users,the system security rate is studied.A joint design of the power allocation at the transmitter and phase shift matrices for reflection and transmission at the STAR-RIS is conducted,in order to maximize the worst achievable security data rate(ASDR).Since the problem is nonconvex and hence challenging,a particle swarm optimization(PSO)based algorithm is developed to tackle the problem.Both the cases of continuous and discrete phase shift matrices at the STAR-RIS are considered.Simulation results demonstrate the effectiveness of the proposed algorithm and shows the benefits of using STAR-RIS in MIMO mutliuser systems.展开更多
文摘针对无人机基站空对地通信链路易受窃听攻击的问题,提出一种基于隐蔽信息映射的广义空间方向调制系统(covert information mapped-generalized spatial and direction modulation,CIM-GSDM),将信息隐藏于激活接收机子集的索引及其选择组合中,引入与合法方信道正交的人工噪声干扰窃听方。为进一步提升系统的传输安全性,研究提出了预编码矩阵和功率分配因子联合优化框架,通过有效管理多波束传输和人工噪声的功率分配,增强系统安全性。首先,推导基于系统安全速率的物理层安全性指标,以此为优化目标,联合优化预编码矩阵和人工噪声功率分配因子。为解决该非凸的联合优化问题,考虑交替优化2个变量,提出基于Nesterov下降的自然梯度下降法,通过快速迭代更新预编码矩阵,解决CIM-GSDM符号候选集规模较大带来的计算复杂度问题。基于合法方信噪比与窃听方干信噪比的乘积最大化准则,推导出功率分配因子的次优闭式解。仿真结果表明,所提优化算法在保证合法方可达到的速率前提下,显著降低窃听方的窃听速率,有效保证CIM-GSDM系统的传输安全性。相比传统波束成形算法及固定功率分配因子的方法,提出算法在安全性能上具有显著优势。
文摘The simultaneous transmitting and reflecting reconfigurable intelligent surface(STAR-RIS)can independently adjust surface’s reflection and transmission coefficients so as to enhance space coverage.For a multiple-input multiple-output(MIMO)communication system with a STAR-RIS,a base station(BS),an eavesdropper,and multiple users,the system security rate is studied.A joint design of the power allocation at the transmitter and phase shift matrices for reflection and transmission at the STAR-RIS is conducted,in order to maximize the worst achievable security data rate(ASDR).Since the problem is nonconvex and hence challenging,a particle swarm optimization(PSO)based algorithm is developed to tackle the problem.Both the cases of continuous and discrete phase shift matrices at the STAR-RIS are considered.Simulation results demonstrate the effectiveness of the proposed algorithm and shows the benefits of using STAR-RIS in MIMO mutliuser systems.
