多维域低零功率通信

Low-to-no-power covert communication based on energydispersion

无线信道的开放性使得无线通信链路极易受到窃听和攻击.随着硬件设备的发展和信号处理技术的进步,无线通信链路面临的安全威胁日益严峻,亟需一种更为有效的防护机制保障无线通信链路的安全.为此,本文从能量博弈的角度提出了基于信号能量弥散的多维域低零功率通信体制,通过隐藏通信信号和行为来避免恶意用户对无线通信链路监听和攻击.该体制以直接序列扩频技术为基础,以通信行为的隐匿为目标,通过将信号能量在时、频、空、码和极化等多维参数空间进行弥散,增加侦听方的能量收集难度,提升信号的隐蔽性.本文以侦听方有关多维域信号参数的先验信息为基础定义信号的隐蔽性,并结合概率论、信息论和信号检测理论建立多维域低零功率通信系统的数学模型,分析了系统的可达性能极限,揭示了侦听方先验知识对隐蔽通信速率的影响,为后续研究工作的开展奠定了理论基础.结果显示通过信号能量的多维域弥散合法用户间的通信速率能够突破传统1/2次幂的变化规律,实现高效隐蔽的信号传输.

With advances in computing and signal processing technologies,wireless communication systems are facing severe security threats,necessitating effective countermeasures.Unlike traditional secure communication schemes,covert communication should hide not only information content but also data transmission activity from adversaries.To this end,we propose an energy dispersion-based covert communication scheme to ensure that communication signal detection by adversaries has close-to-zero probability.The proposed scheme spreads the energy of transmitted signals throughout the whole parameter space to limit the signal detection capability of adversaries and improve the covertness of signal transmission.By defining the covertness of transmitted signals with respect to the adversaries’prior knowledge of parameter spaces,we study the modeling of energy dispersion-based covert communication systems and analyze their fundamental performance limitations.With these analytical results,we further investigate the impacts of adversaries’prior knowledge on the achievable throughput of covert communications.These results demonstrate that the dispersion of signal energy can degrade the performance of coherent signal detection so that the achievable throughput of the covert communication system does not necessarily follow the power-law decrease observed in existing work on the low probability of detection communications.This work lays the theoretical foundation for covert communication based on energy dispersion.