基于FPGA的无线光通信调制技术研究及实现

发布时间：2018-01-05 18:05

本文关键词：基于FPGA的无线光通信调制技术研究及实现　出处：《北京邮电大学》2014年硕士论文　论文类型：学位论文

【摘要】：无线光通信使用光波作为载体来传输信息,可以缓解日益紧张的无线射频频谱资源,并具有带宽高、辐射低、抗干扰等光通信的特点,因而受到国内外的重视,成为无线领域研究的热点之一。无线光通信在国内外发展迅速,随着相关技术的发展,如发光二极管寿命增长及调制带宽增高,光电探测器灵敏度增高以及响应速度增快等,有着较大的发展潜力和应用前景。为了提高无线光通信的频谱利用率,可以通过提高发射光功率,增大光电探测器的探测面积,选择适合大气窗口的激光波长,选择合适系统的调制解调技术等方法实现,但由于激光对人眼伤害,不可盲目提高系统发射光功率,探测面积增大导致系统频带利用率降低等。在目前这种情况和现有的光学器件发展基础上,需要尽可能在移动设备上减少能量消耗,寻找适合紫外光通信的调制解调技术来提高紫外光通信的性能显得尤为重要。本文首先概括分析了无线光谱的特性,阐述了无线光通信的通信特点及原理；为了更好的提高通信系统的性能,系统除了使用大功率激光器、高灵敏度的激光探测器以及选择适合大气窗口的激光波长外,还可以通过采用不同的调制方式来提高系统的可靠性和有效性,本文设计实现了目前适合紫外光通信的开关键控调制OOK,脉冲位置调制PPM、差分脉冲位置调制DPPM、数字脉冲间隔调制DPIM、双头脉冲间隔调制DH-PIM以及等长脉冲间隔调制FDPIM等多种调制解调技术,并对各种调制技术的进行了实验测试得出多种调制解调技术的平均光功率、传输容量、传输速率、误码率等通信性能对比图,分析后得出结论：各种调制方式在频谱利用率、误码性能上还有待进一步提高；本文提出使用当前3G通信的核心扩频技术方案作为调制方式,设计并实现了紫外光扩频通信实验系统,通过实验验证了扩频编码后的信息经过传输后能明显降低误码率,且误码率随着扩频序列周期的增加而减小；最后根据扩频技术原理和PN码的正交性,提出了基于紫外光通信的多用户扩频通信,并设计了实现方法,做技术总结和展望。
[Abstract]:Wireless optical communication uses optical wave as a carrier to transmit information, which can alleviate the increasingly tight radio frequency spectrum resources, and has the characteristics of high bandwidth, low radiation, anti-jamming and other optical communication characteristics, so it has been paid attention to at home and abroad. It has become one of the hotspots in wireless field. Wireless optical communication is developing rapidly at home and abroad. With the development of related technologies, such as the increase of light-emitting diode lifetime and modulation bandwidth, the sensitivity of photodetector and the increase of response speed, etc. In order to improve the spectrum efficiency of wireless optical communication, the laser wavelength suitable for atmospheric window can be selected by increasing the power of emitting light and increasing the detection area of photodetector. The method of modulation and demodulation is chosen, but the laser can't increase the optical power of the system blindly because of the damage to the human eyes. On the basis of the current situation and the development of optical devices, it is necessary to reduce the energy consumption on mobile devices as much as possible. It is very important to find suitable modulation and demodulation technology to improve the performance of ultraviolet communication. In this paper, the characteristics of wireless spectrum are analyzed, and the communication characteristics and principles of wireless optical communication are described. In order to improve the performance of the communication system, in addition to the use of high-power lasers, high-sensitivity laser detectors and the selection of laser wavelength suitable for the atmosphere window. Different modulation methods can also be used to improve the reliability and effectiveness of the system. In this paper, open key modulation OOK and pulse position modulation PPM, which are suitable for UV communication, are designed and implemented. Differential pulse position modulation (DPP), digital pulse interval modulation (DPIM), dual-head pulse interval modulation (DH-PIM) and equal-length pulse interval modulation (FDPIM) are used in this paper. The average optical power, transmission capacity, transmission rate and bit error rate of various modulation and demodulation techniques are compared with each other. After analysis, it is concluded that the spectrum efficiency and error performance of various modulation methods need to be further improved; In this paper, we design and implement the experimental system of ultraviolet spread spectrum communication using the core spread spectrum technology of 3G communication as modulation mode. It is verified by experiments that the BER can be significantly reduced after the spread spectrum coding information is transmitted, and the BER decreases with the increase of the spread spectrum sequence cycle. Finally, according to the principle of spread spectrum technology and the orthogonality of PN code, the multi-user spread spectrum communication based on ultraviolet light communication is proposed, and the implementation method is designed, and the technical summary and prospect are made.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1

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