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针对非实时通信对安全性要求高且信道中存在噪声的问题,提出了基于超混沌掩盖调制的自适应异步抗噪声保密通信方案。通信原理是由超混沌Lorenz系统生成四个状态变量的伪随机向量,并通过信号增益将它们调整到同一区间;再由分段线性混沌映射(PWLCM)生成两个向量,用于在四个状态变量之间随机切换选取和确定动态时滞步长,以生成载体信号;然后将预编码后的二进制信息成对掩盖到载体信号中,添加高斯噪声后发送出去。实验结果分析发现最小信号增益和噪声系数的比值稳定在一个小区间[0.08,0.11]内,如果把该比值设置成某个大于该区间上限的值,则比特误码率可达到零,因此接收端可在噪声信道中接收并完美恢复出被掩盖信号。该方案利用超混沌系统的非线性动力学特性,能够在噪声信道中自适应实现异步保密通信,数值仿真验证了其有效性。
Aiming at the problem of non-real-time communication requiring high security and noises in the channel, an adaptive asynchronous anti-noise secure communication scheme based on hyperchaos mask modulation is proposed. The principle of communication is that the pseudo-random vectors of four state variables are generated by the hyperchaotic Lorenz system and adjusted to the same interval by the signal gain. Two pieces of vector are generated by the piecewise linear chaotic mapping (PWLCM) Random switching between variables selects and determines the dynamic time-delay step to generate a carrier signal; then, the precoded binary information is masked to the carrier signal in pairs, and the Gaussian noise is added and sent out. Experimental results show that the ratio of the minimum signal gain to the noise figure is stable within a small interval [0.08,0.11]. If the ratio is set to a value greater than the upper limit of the interval, the bit error rate can reach zero, thus receiving The end can receive in the noise channel and perfectly recover the masked signal. The scheme makes use of the nonlinear dynamics of the hyperchaotic system and can realize asynchronous secure communication adaptively in the noise channel. Numerical simulation shows its effectiveness.