在存在恶意干扰者的四节点网络中,恶意干扰者通过发送相关干扰破坏合法通信。针对该安全问题,本文提出了一种源信号和结构性噪声联合发送的安全传输方法,其中,结构性噪声是指合法通信双方共享的结构性码字,它只干扰非合作节点,从而提高系统安全性能。具体步骤为,首先建立发送方和恶意干扰者之间以安全速率为目标函数的连续零和博弈模型;然后根据信道状态确定各自的策略集,并分析策略集对应的纳什均衡;最后利用均衡解指导发送方合理分配源信号和结构性噪声的功率。数值仿真表明所提方法下的安全速率比原有方案的要高。
In a four-node network in the presence of a malicious jammer, the correlated jamming from the malicious jammer disrupted the legitimate communication. To cope with this security problem, this paper proposed a secure transmission method of transmitting the source signals and the structural noise synchronously. The structural noise is a kind of structural word known to the legitimate node, thus only jamming the non-cooperative nodes and enhancing the security. The detail steps are the following. First, the transmitter and the malicious jammer were modeled as a continuous zero-sum game with the utility function of secrecy rate. Then, their strategies were determined according to the channel state, and the corre- sponding Nash equilibrium was analyzed. Finally, the equilibrium was used to guide the power allocation for source signals and structural noise to enhance the system performance. Numerical simulation results show that the average secrecy rate of the proposed method is higher than the original scheme.