基于紫外的无线光通信数字滤波与扩频技术研究

发布时间：2018-03-21 23:10

本文选题：无线光通信　切入点：紫外光通信　出处：《北京邮电大学》2015年硕士论文　论文类型：学位论文

【摘要】：无线光通信是近年来兴起的无线通信与光通信结合的前沿交叉学科,其中基于紫外的无线光通信因其独特的散射传播特性而在短距离准视距甚至非视距通信方向受到越来越多的关注。紫外无线光通信通常利用紫外日盲波段,是对常规通信方式的补充,相对于其他无线通信方式,紫外光通信具有保密性好、背景干扰小等特点,可应用于需要保密通信的场合,因此具有重要的研究价值。紫外无线光通信技术研究起步较晚,仍处于快速发展阶段,尚有一些核心技术问题有待解决。国内研究目前多集中于信道仿真理论模型的建立以及提高紫外无线光通信系统性能方法等方面,已取得了定成果。紫外信道损耗非常大,因此通常接收端所能接到的光信号非常微弱,若在有带外杂光以及电路噪声干扰的情况下进行通信,则需要采用去噪声、抗干扰技术以提高通信系统的性能,所以紫外无线通信系统的探测端噪声、数字滤波去噪方法、紫外扩频通信方案等研究具有重要意义。紫外光电转换器件作为接收端核心器件,其噪声性能对紫外光通信系统性能具有重要影响。论文归纳总结了几种常见紫外光电探测器的噪声因素,并进行了实测分析。为了降低各类噪声对紫外通信系统性能的影响,论文设计实现并验证了均值滤波和中值滤波两种滤波方法,在此基础上设计并实现了针对紫外通信特性的自适应滤波方法,通过实验测试,该方案在室外噪声干扰下,可以有效提高紫外通信系统信噪比达8dB。为了提高紫外通信系统的抗多径衰落和抗干扰能力,论文提出了将扩频技术应用于紫外通信系统的方案,并进行了理论分析和系统仿真,设计实现了OOK(On-Off Keying)、7-SIK(Sequence Inversion Keying,SIK)、63-SIK调制下的紫外扩频通信实验系统,实测结果表明该方案能够有效提高紫外通信系统的误码率性能。由于受限于实验室器件的影响,实验室搭建的紫外通信系统距离通常较短,通过对基于蒙特卡罗紫外通信信道模型的分析和对实际噪声环境的测量,论文对紫外通信距离进行了理论推算。
[Abstract]:Wireless optical communication (WO) is a frontier interdiscipline of wireless communication and optical communication, which has emerged in recent years. Among them, ultraviolet wireless optical communication has attracted more and more attention in short range quasi-line-of-sight and even non-line-of-sight communication due to its unique scattering propagation characteristics. Ultraviolet wireless optical communication usually uses ultraviolet sun-blind band. Compared with other wireless communication modes, UV communication has the characteristics of good confidentiality and low background interference, so it can be applied to the occasions where secure communication is needed, so it has important research value. The research of ultraviolet wireless optical communication technology started late and is still in the rapid development stage. There are still some core technical problems to be solved. At present, many domestic researches have focused on the establishment of theoretical model of channel simulation and the methods of improving the performance of ultraviolet wireless optical communication system, and have achieved certain results. Therefore, the optical signal received by the receiver is usually very weak. If there is out-of-band clutter and circuit noise interference, it is necessary to use de-noise and anti-jamming techniques to improve the performance of the communication system. Therefore, it is of great significance to study the detection end noise, the digital filtering denoising method and the ultraviolet spread spectrum communication scheme of the ultraviolet wireless communication system. As the core device of the receiver, the noise performance of the UV photovoltaic device has an important effect on the performance of the ultraviolet communication system. This paper summarizes the noise factors of several common UV photodetectors, and analyzes the noise factors of several common UV photodetectors. In order to reduce the influence of all kinds of noise on the performance of ultraviolet communication system, two filtering methods, mean filter and median filter, are designed and verified in this paper. On this basis, an adaptive filtering method for ultraviolet communication characteristics is designed and implemented. The experimental results show that the proposed scheme can effectively improve the signal-to-noise ratio (SNR) of UV communication system up to 8 dB under outdoor noise interference. In order to improve the anti-multipath fading and anti-interference ability of the ultraviolet communication system, the scheme of applying spread spectrum technology to the ultraviolet communication system is put forward, and the theoretical analysis and system simulation are carried out. An experimental system of ultraviolet spread spectrum communication based on OOK(On-Off Keyingence Inversion sequence and SIKN 63-SIK modulation is designed and implemented. The experimental results show that the proposed scheme can effectively improve the BER performance of the UV communication system. Due to the influence of laboratory devices, the proposed scheme can effectively improve the BER performance of the UV communication system. The distance of the ultraviolet communication system built in the laboratory is usually short. The ultraviolet communication distance is calculated theoretically by analyzing the channel model based on Monte Carlo ultraviolet communication and measuring the actual noise environment.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.1

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