基于H-PPM的可见光通信系统RS编码性能分析

为了改善复杂交通环境下湍流信道的光强闪烁对信号的影响，研究了大气湍流光强闪烁的系统模型，并且针对PPM和DPIM等调制方法存在的问题，提出一种新型的无线光通信调制方法——头脉冲位置调制(head pulse position modulation，H-PPM)。根据湍流信道的特点，推导出基于H-PPM的可见光通信系统未编码时与RS(Reed-Solomon)码纠错后的误时隙率公式。数值仿真曲线证明，当系统误码率为10-10时，RS(15, 7)纠错码可以提高约18 dB的编码增益。由此可得，采取H-PPM调制和RS编码相结合可提高信号的质量，更有利于复杂交通环境下的可见光通信。

RS code performance analysis of visible lightcommunication system based on H-PPM

In order to improve the light intensity scintillation effects on signals under the turbulent channel of complex traffic environment, we studied the system model of the atmospheric turbulence intensity scintillation in theory, and put forward a new kind of modulation method of free space optics(FSO), head pulse position modulation(H-PPM), aiming at the existing problem of pulse position modulation (PPM) and differential pulse?position modulation (DPIM) methods.According to the characteristics of turbulent channel, we derived the slot error rate formula of visible light communication system based on H-PPM when encoded with Reed-Solomon(RS) code or not.The results of numerical simulation show that the RS(15, 7) code can improve about 18 dB coding gain when the system bit error rate is 10-10.Therefore, the combination of H-PPM modulation and RS coding can improve the quality of the signal and facilitate the visible light communication in complex traffic environments.