| 摘要: |
| 无线信道的开放特性为未来通信网络安全带来了严峻挑战，相比传统隐蔽通信手段采用定向传输或功率控制的技术手段，环境反向散射技术利用环境中的背景信号作为载波进行通信，为隐蔽通信领域提供了一种创新的思路。为分析其传输性能，研究了基于环境反向散射技术的隐蔽通信(Covert Communications based on Ambient Backscatter Technique，CCABT)的信道容量。首先，通过分析发射信号和接收信号表达式，将CCABT信道建模为乘性干扰信道模型，即背景信号与有用信号为乘积关系。在此基础上，推导了其信道容量及最优输入分布的半闭式解，并通过二分法求解了其最优输入分布。然后，在考虑莱斯信道衰落下，进一步分析得到了CCABT信道的遍历容量表达式。仿真结果表明，相同干信比时，CCATB相比扩频的通信容量提升了122.7%。此外，在隐蔽性能不变的情况下，CCABT的信道容量随着环境信号的增强而提高，尤其适用于强干扰环境。 |
| 关键词: 隐蔽通信 环境反向散射通信 乘性干扰信道 信道容量 遍历容量 |
| DOI：10.20079/j.issn.1001-893x.251011001 |
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| 基金项目: |
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| Covert Communications Based on Ambient Backscatter Technique and Performance Analysis |
| MA Jianhui |
| (Southwest China Institute of Electronic Teechnology，Chengdu 610036，China) |
| Abstract: |
| The open nature of wireless channels brings significant challenges to the security of future communication networks.In contrast to traditional covert communication methods that adopt directional transmission or power control techniques，the ambient backscatter technique utilizes ambient background signals as carriers for information transmission，thus providing a novel approach to covert communications.To evaluate its transmission capabilities，the channel capacity of covert communications based on ambient backscatter technology (CCABT) is investigated.Firstly，by analyzing the expressions of the transmitted and received signals，the CCABT channel is modeled as a multiplicative interference channel，which is characterized by a product relationship between the background signal and the useful signal.Based on this model，the CCABT’s channel capacity with a semi-closed-form expression for its optimal input distribution is derived，whose numerically solution is further obtained by the bisection method.Subsequently，the ergodic capacity of the CCABT channel is studied and derived under the Rician fading model.Simulation results indicate that，under the same interference-to-signal ratio，the channel capacity of CCATB is 122.7% higher than that of spread spectrum technology.Furthermore，while maintaining the same level of covert performance，the channel capacity of the CCABT channel increases with the enhancement of ambient electromagnetic signals，thus making it especially fit for strong interference cases. |
| Key words: covert communications ambient backscatter communication multiplicative interference channel channel capacity ergodic capacity |
《电讯技术》编辑部 