毕业论文----无线通信中ppm对大气的影响.docVIP

电 子 科 技 大 学 UNIVERSITY OF ELECTRONIC SCIENCE AND TECHNOLOGY OF CHINA 学 士 学 位 论 文 BACHELOR DISSERTATION 论文题目 无线光通信中的延时误差对PPM脉冲系统的影响 学生姓名 　 学　　号 专　　业 电子信息科学与技术 学　　院 物理电子学院 指导教师 指导单位 电子科技大学物理电子学院 2010年 　6　 月 　7　 日摘 要 本课题所研究大气湍流环境下延时误差对PPM系统性能影响近地无线光通信链路通过大气信道受天气因素的影响很大。大气温度和压力的不均匀性可导致激光在传输路径上折射率发生变化造成接收信号强度起伏和相位抖动导致差错率急剧上升。因此除了选择合适的调制方式之外还应采用纠错编码来提高无线光通信的链路性能。很多文献报道了采用纠错编码的无线光PPM 通信系统的性能但均未考虑差错编码如何与PPM 结合的问题 。通过对光无线通信系统的研究得出一种适合于光无线通信系统中PPM调制的实现方法进一步研究无线通信中的延时误差对PPM脉冲系统的影响ABSTRACT This subject studied the atmospheric turbulence delay error on the PPM system performance. Take the wireless optical communication link to the channel through the atmosphere, great weather factors.?Atmospheric temperature and pressure can lead to inhomogeneity of the transmission path of laser refractive index changes, resulting in received signal strength fluctuation and phase jitter, resulting in the error rate increased dramatically.?Therefore, in addition select the appropriate modulation, the error correction code should be used to improve the performance of wireless optical communications link.?A lot of papers reported the use of error-correcting codes for wireless optical PPM communication system performance, but no error code considering how the problem of combining PPM. Therefore, optical wireless communication systems through research, come up with a suitable optical wireless communication system in the realization of PPM modulation method, were obtained on the basis of strong and weak turbulent environment, frame error rate PWE and the normalized of the relationship between the timing error. In addition, when the system obtained by simulation timing error exists, the scintillation index, APD gain and the average level of PPM modulation parameters on the PPM optical pulse system performance. Further research on wireless communications in the delay error on the impact of PPM pulse system has some value. Key Words: Wireless Optical Communicatio