| 摘要: |
| 随着5G和物联网（Internet of Things,IoT）的快速发展，低功耗通信和物理层安全已成为通信系统中亟待解决的重要问题。为应对这一挑战，提出了一种空时移键控(Space-Time Shift Keying,STSK)与可重构智能表面(Reconfigurable Intelligent Surface,RIS)相结合的索引调制方案，旨在传输额外索引信息的同时提升系统的物理层安全性。在发射功率、符号功率和RIS相移约束下联合优化了符号星座、STSK色散矩阵和发射端功率分配，以最大化系统在连续输入连续输出无记忆信道(Discrete-input Continuous-output Memoryless Channel,DCMC)下的保密容量。提出了一种黎曼共轭梯度下降算法，并导出了变量的理论梯度和投影梯度，使得算法能够同时兼顾收敛速度和稳定性。仿真结果表明，所提方案在传输额外比特的同时，有效降低了窃听者的窃听性能，并且与基准算法相比，在更高反射单元数量下，所提算法可以求出更加优质的解，DCMC保密容量能够达到容量上限的87.8%。 |
| 关键词: 空时移键控(STSK) 物理层安全(PLS) 可重构智能面(RIS) 流形优化 |
| DOI：10.20079/j.issn.1001-893x.250116001 |
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| 基金项目:国家自然科学基金资助项目（62271368，62371367）；中央高校基本科研业务费（QTZX23066）；陕西省重点研发计划（2023-ZDLGY-50） |
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| A Secure Transmission Scheme for Space-Time Shift Keying Systems |
| MU Huihui,CHEN Jian,LYU Lu,YANG Long |
| (School of Telecommunications Engineering,Xidian University,Xi’an 710071,China) |
| Abstract: |
| With the rapid development of 5G and the Internet of Things(IoT),low-power communications and physical layer security(PLS) have become critical issues that need to be addressed in communication systems.To tackle this challenge,a communication scheme combining space-time shift keying(STSK) with reconfigurable intelligent surface(RIS) is proposed,aiming to enhance the system's PLS while transmitting additional index information.Under constraints of transmit power,symbol power,and RIS phase shifts,the symbol constellation,STSK dispersion matrices,and transmit power allocation are jointly optimized to maximize the secrecy capacity of the system over discrete-input continuous-output memoryless channel(DCMC).A Riemannian conjugate gradient descent algorithm is developed,with theoretical gradients and projected gradients derived for variables,enabling the algorithm to balance convergence speed and stability simultaneously.Simulation results demonstrate that the proposed scheme effectively reduces eavesdropper performance while transmitting additional bits.Compared with benchmark algorithms,the proposed algorithm achieves superior solutions with higher numbers of reflective units,reaching 87.8% of the DCMC secrecy capacity upper bound. |
| Key words: space-time shift keying(STSK) physical layer security(PLS) reconfigurable intelligent surface(RIS) manifold optimization |
《电讯技术》编辑部 