近地无线光通信技术研究

【作者】 吴刚；

【导师】 王宗欣； 吴昕；

【作者基本信息】 复旦大学 ， 电子与通信工程， 2009， 硕士

【摘要】 无线光通信技术有诸多优点,比如:大容量,低功耗,体积小,质量轻等。无线光通信可以广泛应用于军事和经济建设的多个领域。近些年,随着适合无线光通信应用的先进通信电子技术的成熟,国内外掀起了研究的热潮,无线光通信技术是光通信发展的重要方向之一。本文主要对近地大气光通信系统进行了研究。首先,介绍分析了无线光通信领域的几个关键技术。包括:大气信道对无线光通信系统的影响,进而引出自适应光学技术的应用;光天线系统的应用;大功率激光器和高灵敏度光电检测器;对目标的捕获跟踪和瞄准(ATP)技术。本文还讲述了无线光通信系统的设计。本文重点提出了一种进行帧处理的信号调制的方法。本文从符号结构、平均发射功率、带宽效率及误时隙率等方面对其性能进行了详细的分析,并与开关键控调制(OOK)、脉冲位置调制(PPM)以及数字脉冲间隔调制(DPIM)进行了比较。符号的同步是实现正确解调的关键。根据上述调制的方法,本文提出了一种基于帧同步的符号同步方法(SSBFS)。本文详细讲述了该方法的实现过程,并且主要从同步概率,伪失步平均时间间隔和平均建立时间三个方面来衡量其同步的性能。并且与一种用于PPM信号的同步方法进行比较,分析其优缺点。通过实际的计算分析可以得出SSBFS的同步方法具有电路设计简单,同步概率高,伪失步平均时间间隔长和平均建立时间短的特点,可应用于低速无线光通信系统。更多还原

【Abstract】 Optical wireless communication has several advantages,such as big capacity,low power consumption,small volume and light weight etc.Optical wireless communication can find wide applications in the military and commercial fields and it has a great potential.More and more institudes are engaged in studying the technology with the development of electronics. Optical wireless communication play an important role in the development of optical communication.The dissertion emphasis on the study of atmospheric optical communication which is near the ground.Firstly,the basic principle of the optical wireless communication is described.Secondely,the key technologies are put forward emphatically which include of the atmospher channel,adaptive optical technology,high power laser and high sensitivity detector,fast and precision capture,tracking and aiming of communication link,optical anttenne.Then,the dissertion describes the designment of optical wireless communication system.The dissertion raises a modulation which uses a special frame scheme.The symbol structure,the average transmission power and bandwidth efficiency are analyzed.On the meantime,the slot error rate is also analyzed on the given model.The modulation is campared with OOK,PPM and DPIM.Symbol synchronization is necessary for accurate demodulation.The dissertion present a novel symbol synchronization based on frame Synchronization.The performance of frame synchronization is studied after addressing its operation principle and compared with a symbol synchronization for PPM.The results show that the method has the merit of short build-up time,high sync probability,self-adjustment and easily practicality.It is a good method to be used in low rate optical wireless communication system.更多还原