本文選題：相干光通信　切入點(diǎn)：16-QAM調(diào)制信號　出處：《北京交通大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著信息時代的來臨,傳統(tǒng)基于強(qiáng)度調(diào)制/直接檢測的低速光通信系統(tǒng)已無法滿足日益增長的帶寬需求。而基于高階調(diào)制、相干檢測和數(shù)字信號處理技術(shù)的高速相干光通信網(wǎng)絡(luò)具有高速率、高頻譜利用率、低成本等優(yōu)勢,是下一代高速通信網(wǎng)的發(fā)展方向之一。結(jié)合相干檢測和數(shù)字信號處理技術(shù)的數(shù)字相干光接收機(jī),不僅可以充分保留載波幅度、相位及偏振等信息,還可以在電域中對光纖鏈路損傷及噪聲進(jìn)行很好的恢復(fù)和補(bǔ)償,成為近年來光通信領(lǐng)域的研究熱點(diǎn)。本文主要圍繞基于16-QAM調(diào)制碼型、相干檢測及數(shù)字信號處理技術(shù)的高速相干光通信系統(tǒng)進(jìn)行研究,重點(diǎn)研究了發(fā)射端激光器與本地振蕩器間引入的頻偏及相位噪聲對系統(tǒng)性能的影響,實現(xiàn)了數(shù)字相干光接收機(jī)對載波頻偏和載波相位的準(zhǔn)確估計及恢復(fù)。主要完成以下工作:(1)研究方型16-QAM光信號的生成方式及原理,采用四電平驅(qū)動IQ調(diào)制器的光信號生成方式搭建112Gb/s 16-QAM相干光通信系統(tǒng)仿真平臺,并利用載波頻偏估計算法及載波相位估計算法對接收信號進(jìn)行載波恢復(fù)。(2)研究基于部分星座點(diǎn)和基于訓(xùn)練序列的載波頻偏估計算法。比較分析在112Gb/sl6-QAM調(diào)制格式相干光通信系統(tǒng)中,兩種載波頻偏估計算法的估計范圍、估計精度和運(yùn)算復(fù)雜度,討論了系統(tǒng)殘余頻偏對載波相位估計的影響。(3)研究多種載波相位估計算法。本文對目前性能較好、可適用于16-QAM及其他高階調(diào)制碼型的載波相位估計算法進(jìn)行研究,并從改進(jìn)型ViterbiViterbi算法和盲相位搜索(BPS,Blind Phase Search)級聯(lián)算法對其進(jìn)行分類闡述,比較并分析八種載波相位估計算法在16-QAM相干光通信系統(tǒng)中的線寬容忍度及硬件復(fù)雜度。(4)提出了一種基于BPS的線性逼近(LA,Line Approximation)載波相位估計算法。闡述了 LA載波相位估計算法的基本原理和實現(xiàn)流程,通過仿真得到該算法的最佳測試相位點(diǎn),同時分析了 LA載波相位估計算法的誤碼率、線寬容忍度、硬件復(fù)雜度及頻偏容忍度。利用LA載波相位估計算法對112Gb/s 16-QAM相干光通信系統(tǒng)接收信號的相位進(jìn)行恢復(fù),仿真結(jié)果顯示,LA算法的激光器線寬容忍度與BPS算法相近;其硬件復(fù)雜度比BPS算法的硬件復(fù)雜度降低了2.13/2.18/2.91/2.06(乘法器/加法器/比較器/判決器)倍;當(dāng)殘余頻偏超過30MHz時,LA算法對接收信號的恢復(fù)能力優(yōu)于BPS算法。
[Abstract]:With the advent of the information age, the traditional low-speed optical communication systems based on intensity modulation / direct detection can no longer meet the increasing bandwidth requirements. The high speed coherent optical communication network based on coherent detection and digital signal processing has the advantages of high rate, high spectral efficiency and low cost. Digital coherent optical receiver combined with coherent detection and digital signal processing technology can not only fully retain carrier amplitude, phase and polarization information. It can also be used to recover and compensate the damage and noise of optical link in the electric domain, which has become the research hotspot in the field of optical communication in recent years. This paper mainly focuses on the modulation code type based on 16-QAM. The high speed coherent optical communication system based on coherent detection and digital signal processing technology is studied. The influence of frequency offset and phase noise introduced between the transmitter laser and the local oscillator on the performance of the system is studied. The accurate estimation and recovery of carrier frequency offset and carrier phase are realized by digital coherent optical receiver. The following work is accomplished: 1) the generation method and principle of square 16-QAM optical signal are studied. The simulation platform of 112Gb / s 16-QAM coherent optical communication system is built by using the optical signal generation method of four-level drive IQ modulator. The carrier frequency offset estimation algorithm based on partial constellation and training sequence is studied by using carrier frequency offset estimation algorithm and carrier phase estimation algorithm for received signal. A comparative analysis is made in 112Gb / sl6-QAM modulation format coherent optical communication system. The estimation range, estimation accuracy and computational complexity of two carrier frequency offset estimation algorithms are discussed. The influence of residual frequency offset on carrier phase estimation is discussed. The carrier phase estimation algorithm suitable for 16-QAM and other high-order modulation code types is studied, and the improved ViterbiViterbi algorithm and the blind phase search BPS-Blind Phase search algorithm are classified and described. Comparing and analyzing the linewidth tolerance and hardware complexity of eight carrier phase estimation algorithms in 16-QAM coherent optical communication systems, a linear approximation line approximation algorithm based on BPS is proposed. The LA carrier phase estimation algorithm is described. The basic principle and implementation flow of bit estimation algorithm, The optimal test phase point of the algorithm is obtained by simulation. Meanwhile, the error rate and line width tolerance of the LA carrier phase estimation algorithm are analyzed. Hardware complexity and frequency offset tolerance. The phase recovery of 112Gb / s 16-QAM coherent optical communication system is performed by using LA carrier phase estimation algorithm. The simulation results show that the linewidth tolerance of the LA algorithm is similar to that of BPS algorithm. The hardware complexity of the algorithm is 2.13 / 2.18 / 2.91 / 2.06 (multiplier / adder / comparator / decider), and when the residual frequency offset exceeds 30MHz, the recovery ability of the LA algorithm is better than that of the BPS algorithm.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN929.1

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本文編號：1576613