基于环境反向散射技术的隐蔽通信及其性能分析OA

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.