基于混沌Duffing振子的BPSK信号K-means聚类解调方法

K-means clustering demodulation method for BPSK signal based on chaotic Duffing oscillator

针对二进制相移键控(binary phase shift keying,BPSK)信号在低信噪比下解调误码率较高的问题,提出了一种基于混沌Duffing振子的K-means解调方法。该方法的思想是根据混沌Duffing振子系统对初值的敏感性以及对噪声的免疫特性,低信噪比下Duffing振子系统输入BPSK信号时,由于BPSK信号相位在0°和π之间的跳变从而导致Duffing振子输出相轨迹状态发生改变。针对相轨迹状态的变化,采用K-means聚类算法对相轨迹进行迭代求质心,根据收敛后的质心间距大小对BPSK信号进行判决解调。仿真结果表明,与现有的几种解调方法相比较,基于混沌Duffing振子的BPSK信号K-means聚类解调方法在低信噪比下解调速度、解调精度等方面都有了较大的提高。

For the BPSK signal always got high bit error rate(BER) when demodulated in a low signal-to-noise ratio(SNR)environment,this paper proposed a K-means clustering demodulation method based on chaos Duffing oscillator to reduce the BER. This study accorded to two characteristics of Duffing oscillator,not only it was very sensitive to the initial value,but also had certain immunity to noise. The phase of BPSK signal change between 0° and π caused state change in the Duffing oscillator’s phase orbits,and used a K-means clustering method to find the centroid of phase orbit by iteration,then demodulated BPSK signal by calculating the distance of centroids. Simulation results show that the K-means clustering demodulation method has a great improvement in the calculation rate and the demodulation accuracy in a low SNR environment.