为提高可见光通信系统安全性, 并进一步降低系统的误码率, 将具有伪随机特性的混沌序列、扩频技术和脉冲位置调制(PPM)引入到发光二极管(LED)光通信系统, 实现了一种基于混沌脉冲位置调制(CPPM)的LED光通信系统。在加性高斯白噪声(AWGN)信道下, 分别分析了信噪比对PPM系统误码率, 及密钥、信噪比和混沌序列的长度对CPPM系统误码率的影响。仿真结果表明: 当混沌序列的长度大于32为时, CPPM系统优于PPM系统, 可降低系统的误码率, 提高系统的安全性。

In order to improve the security of the visible light communication system and further reduce the bit error rate of the system, chaotic sequences with pseudo-random characteristics, spread spectrum techniques, and pulse position modulation (PPM) are introduced into the light-emitting diode (LED) optical communication system. An LED optical communication system based on chaos pulse position modulation (CPPM) is realized. Under the additive white Gaussian noise(AWGN) channel, the influence of signal-to-noise ratio(SNR) on bit error rate of PPM system is analyzed. At the same time, the influence of the key, SNR and the length of chaotic sequence on the bit error rate of CPPM system are analyzed. Simulation results show that when the length of chaotic sequence is greater than 32, the CPPM system is superior to the PPM system, which can reduce the bit error rate of the system and improve the security of the system.