本文選題：空間光通信　切入點(diǎn)：大氣信道　出處：《北京郵電大學(xué)》2015年碩士論文

【摘要】：自由空間光通信(Free Space Optical Communication, FSO)是一種以激光作為載波,在自由空間中傳輸信息的無(wú)線通信方式。與傳統(tǒng)的射頻(Radio Frequency, RF)無(wú)線通信相比,FSO具有可用頻譜寬、保密性好、抗電磁干擾能力強(qiáng)、功耗低、體積小和傳輸容量大等優(yōu)點(diǎn)。因此,FSO在星間、星地和地面通信中都極具應(yīng)用潛力。國(guó)內(nèi)外對(duì)自由空間光通信的研究已經(jīng)進(jìn)行了很多年,包括發(fā)射光源、調(diào)制格式、大氣信道、跟蹤捕獲技術(shù)及接收技術(shù)。 然而,激光在大氣信道中傳輸會(huì)受到湍流的嚴(yán)重影響。湍流是造成FSO信道畸變的最主要原因,會(huì)對(duì)激光產(chǎn)生一系列的影響,從而導(dǎo)致通信質(zhì)量降低,嚴(yán)重時(shí)甚至可能造成通信的中斷。因此,研究大氣信道模型具有重要意義。由于大氣信道的影響,提高接收端靈敏度對(duì)FSO系統(tǒng)性能的提升也至關(guān)重要。因此,研究接收技術(shù)和調(diào)制格式以提高靈敏度很有必要。另外,相比于光纖信道,FSO信道更適于使用空間模式復(fù)用技術(shù),以提高傳輸容量。本文主要從大氣信道、接收技術(shù)和復(fù)用技術(shù)三個(gè)方面研究了空間光通信的關(guān)鍵技術(shù)。主要工作如下： 一、研究大氣信道模型。基于Kolmogorov大氣湍流理論,利用相位屏法建立了大氣信道模型,對(duì)激光在湍流中的傳輸進(jìn)行了數(shù)值仿真。利用空間光調(diào)制器搭建了室內(nèi)大氣湍流仿真平臺(tái),實(shí)驗(yàn)研究了不同強(qiáng)度湍流對(duì)激光束的影響,包括遠(yuǎn)場(chǎng)強(qiáng)度分布和接收光功率。 二、研究了接收技術(shù)。仿真分析了空間分集接收,實(shí)現(xiàn)并比較了三種常用合并算法在BPSK和QPSK調(diào)制格式下的性能。分析了相干接收技術(shù)及數(shù)字信號(hào)處理算法,并進(jìn)行了數(shù)字相干高速空間光通信實(shí)驗(yàn),研究了相干接收技術(shù)在空間光通信中的性能。對(duì)比和分析了多種常用調(diào)制格式的接收靈敏度。 三、研究了軌道角動(dòng)量(Orbit Angular Momentum, OAM)在空間光通信中的應(yīng)用。介紹了基于OAM的空間復(fù)用技術(shù),設(shè)計(jì)了相應(yīng)的相位灰度圖,利用空間光調(diào)制器成功將普通高斯光束轉(zhuǎn)換成任意階的OAM光束。
[Abstract]:Free Space Optical Communication (FSO) is a wireless communication mode in which laser is used as carrier to transmit information in free space.Compared with the traditional radio frequency communication, FSO has the advantages of wide spectrum, good confidentiality, strong anti-electromagnetic interference, low power consumption, small volume and large transmission capacity.Therefore, FSO has great potential in intersatellite, terrestrial and terrestrial communications.The research on free space optical communication has been carried out for many years, including emission light source, modulation format, atmospheric channel, tracking and capturing technology and receiving technology.However, laser propagation in atmospheric channels will be seriously affected by turbulence.Turbulence is the main cause of FSO channel distortion, which will have a series of effects on the laser, which leads to the decrease of communication quality and even the interruption of communication.Therefore, it is of great significance to study the atmospheric channel model.Because of the influence of atmospheric channel, it is also important to improve the performance of FSO system by improving the sensitivity of the receiver.Therefore, it is necessary to study the receiving technique and modulation format to improve the sensitivity.In addition, space mode multiplexing is more suitable than fiber channel FSO to improve transmission capacity.In this paper, the key technologies of space optical communication are studied from three aspects: atmospheric channel, receiving technology and multiplexing technology.The main tasks are as follows:First, the model of atmospheric channel is studied.Based on the Kolmogorov theory of atmospheric turbulence, the model of atmospheric channel is established by using phase screen method, and the propagation of laser in turbulence is simulated numerically.An indoor atmospheric turbulence simulation platform is built using a spatial light modulator. The effects of different intensity turbulence on the laser beam are experimentally studied, including the far-field intensity distribution and the received optical power.Second, the receiving technology is studied.The spatial diversity reception is simulated and analyzed, and the performance of three common merging algorithms in BPSK and QPSK modulation formats is compared.The coherent reception technology and digital signal processing algorithm are analyzed, and the digital coherent high-speed space optical communication experiments are carried out, and the performance of coherent reception technology in space optical communication is studied.The receiving sensitivity of various modulation schemes is compared and analyzed.Thirdly, the application of orbit angular momentum (Orbit Angular momentum) in space optical communication is studied.The spatial multiplexing technology based on OAM is introduced, and the corresponding phase grayscale map is designed. The ordinary Gao Si beam is successfully converted into an arbitrary order OAM beam by using spatial light modulator.
【學(xué)位授予單位】：北京郵電大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN929.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 許楠;劉立人;劉德安;周煜;;星間相干光通信中的光學(xué)鎖相環(huán)[J];激光與光電子學(xué)進(jìn)展;2008年04期

2 ;海洋熱點(diǎn)縱橫[J];海洋世界;2012年06期

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本文編號(hào)：1693957