M分布模型下多跳相干OFDM FSO系统的性能研究

吴昊,王怡. M分布模型下多跳相干OFDM FSO系统的性能研究[J]. 光电工程,2020,47(1):190337. doi: 10.12086/oee.2020.190337
引用本文: 吴昊,王怡. M分布模型下多跳相干OFDM FSO系统的性能研究[J]. 光电工程,2020,47(1):190337. doi: 10.12086/oee.2020.190337
Wu H, Wang Y. Performance study of multi-hop coherent OFDM FSO system over M distribution model[J]. Opto-Electron Eng, 2020, 47(1): 190337. doi: 10.12086/oee.2020.190337
Citation: Wu H, Wang Y. Performance study of multi-hop coherent OFDM FSO system over M distribution model[J]. Opto-Electron Eng, 2020, 47(1): 190337. doi: 10.12086/oee.2020.190337

M分布模型下多跳相干OFDM FSO系统的性能研究

  • 基金项目:
    国家自然科学基金资助项目(51704267);华南理工大学发光材料与器件国家重点实验室开放基金(2019-skllmd-13);深海载人装备国家重点实验室开放基金(702SKL201702)
详细信息
    作者简介:
    通讯作者: 王怡(1980-),女,博士,教授,主要从事自由空间激光通信和星地光通信方面的研究工作。E-mail:wcy16@cjlu.edu.cn
  • 中图分类号: TN929.12

Performance study of multi-hop coherent OFDM FSO system over M distribution model

  • Fund Project: Supported by National Natural Science Foundation of China (51704267), Open Fund of State Key Laboratory of Luminescent Materials and Devices (South China University of Technology) (2019-skllmd-13), and the State Key Laboratory of Deep Sea Manned Vehicles (702SKL201702)
More Information
  • 本文在涵盖了从弱湍流到强湍流的所有信道条件, 能够表征现有大多数湍流信道的M分布模型下, 采用QPSK调制方式研究了多跳相干OFDM FSO系统的性能。系统在中继辅助链路的发射机和接收机之间使用DF中继协议。考虑大气湍流、路径损耗以及瞄准误差对大气信道衰落模型的联合作用, 分别推导出系统的中断概率和误符号率的Meijer G形式的闭合表达式。通过仿真分析了中继链路长度、中继节点数以及子载波个数等关键因素对系统的中断性能和误符号率性能的影响。本研究为中继系统的实际应用奠定了理论基础。

  • Overview: Free space optical (FSO) communication is a bidirectional communication system which is realized by laser signal propagating in atmospheric channel without optical fiber. It can quickly establish communication links in special complex terrain, which is considered as a practical solution to the "last mile problem." Nevertheless, the performance of FSO system is seriously limited by the combined effects of the atmospheric turbulence, atmospheric attenuation, and pointing error. In order to solve this problem, the addition of serial relay technology can effectively alleviate the deterioration of the performance of FSO system. In this paper, we investigate the performance of multi-hop coherent orthogonal frequency division multiplexing (OFDM) FSO system by using quadrature phase shift keying (QPSK) modulation. A generalized model called M distribution is selected, which is suitable for all categories of turbulence ranging from weak to strong and characterizes other existing statistical models of atmospheric turbulence induced fading as its special case. The system uses decode and forward (DF) relay protocol between the transmitter and receiver of the relay auxiliary link. Considering the joint attenuation effects of atmospheric turbulence, path loss and pointing error on the atmospheric channel fading model, we derive the Meijer G closed-form expressions of outage probability and symbol error rate. Furthermore, the effects of key factors, such as relay link length, the number of relay nodes and subcarriers on the outage and SER performance of OFDM FSO system are analyzed through simulations. It can be concluded from the simulation results that increasing the number of relay nodes and subcarriers, longer relay link, and higher atmosphere turbulence intensity will increase the outage probability and SER of the system. According to the analysis, it is suitable that the number of subcarriers and the relay link length are 256 and 1000 m, respectively. In addition, reducing the normalized threshold can reduce the outage probability of the system. Therefore, controlling the appropriate normalized threshold can improve the stability of communication system. At the same time, increasing the average signal-to-noise ratio can improve the system's symbol error performance. It is also known that when a relay node is added to the communication link, the outage probability and SER of OFDM FSO system increase obviously. With the relay node continuing to join, the downward trend of the outage and symbol error performance is getting smaller. Although the outage and symbol error performance is sacrificed with the increase of relay nodes, it solves the design problems of system links, such as making the transmitter and receiver unable to communicate when there are buildings blocking.

  • 加载中
  • 图 1  (a) 多跳FSO通信系统;(b)相干OFDM系统发射端和接收端结构框图

    Figure 1.  (a) Multi-hop FSO communication system; (b) Structural block diagram of transmitter and receiver for coherent OFDM system

    图 2  跳数L=1、2、3、4、5时OFDM FSO系统的中断概率仿真图。(a)强湍流;(b)中湍流;(c)弱湍流

    Figure 2.  Outage probability simulation diagram of OFDM FSO system with hop number L=1, 2, 3, 4, 5. (a) Strong turbulence; (b) Moderate turbulence; (c) Weak turbulence

    图 3  OFDM FSO系统在不同中继间链路长度下的中断概率仿真图。(a) 1000 m;(b) 2000 m;(c) 3000 m

    Figure 3.  Outage probability simulation diagram of OFDM FSO system under different relay link lengths.(a) d=1000 m; (b) d=2000 m; (c) d=3000 m

    图 4  OFDM FSO系统在不同子载波个数N=128、256、512下的中断概率仿真图

    Figure 4.  Outage probability simulation diagram of OFDM FSO system with different subcarriers N=128, 256 and 512

    图 5  跳数L=1、2、3、5时OFDM FSO系统的误符号率仿真图。(a)强湍流;(b)中湍流;(c)弱湍流

    Figure 5.  Symbol error rate simulation diagram of OFDM FSO system with hop number L=1, 2, 3, 5. (a) Strong turbulence; (b) Moderate turbulence; (c) Weak turbulence

    图 6  OFDM FSO系统在不同中继间链路长度下的误符号率仿真图。(a) 1000 m;(b) 2000 m;(c) 3000 m

    Figure 6.  Symbol error rate simulation diagram of OFDM FSO system under different relay link lengths.(a) d=1000 m; (b) d=2000 m; (c) d=3000 m

    图 7  OFDM FSO系统在不同子载波个数N=128、256、512下的中断概率仿真图

    Figure 7.  Outage probability simulation diagram of OFDM FSO system with different subcarriers N=128, 256 and 512

    表 1  多跳相干OFDM FSO系统参数

    Table 1.  The parameters of multi-hop coherent OFDM FSO system

    系统参数 符号 取值
    总散射分量的平均功率 2b0 1.2
    接收端半径/m r 0.1
    光波束宽度/m wz 2.5
    抖动标准差/m δs 0.3
    LOS项的平均功率 Ω 0.4
    LOS和耦合到LOS散射项的确定相位之差 ${\varphi _{\rm{A}}} - {\varphi _{\rm{B}}}$ π/2
    弱大气湍流 $\left( {\delta _{\rm{R}}^2, \alpha , \beta , \rho } \right)$ (4.58, 4.48, 1, 0.75)
    中大气湍流 $\left( {\delta _{\rm{R}}^2, \alpha , \beta , \rho } \right)$ (1.02, 4.37, 3, 0.75)
    强大气湍流 $\left( {\delta _{\rm{R}}^2, \alpha , \beta , \rho } \right)$ (0.46, 6.30, 5, 0.75)
    OFDM的符号周期/ms T 10
    带宽/MHz B 26
    下载: 导出CSV
  • [1]

    付强, 姜会林, 王晓曼, 等.空间激光通信研究现状及发展趋势[J].中国光学, 2012, 5(2): 116–125. doi: 10.3969/j.issn.2095-1531.2012.02.004

    Fu Q, Jiang H L, Wang X M, et al. Research status and development trend of space laser communication[J]. Chinese Optics, 2012, 5(2): 116–125. doi: 10.3969/j.issn.2095-1531.2012.02.004

    [2]

    李晓峰.星地激光通信链路原理与技术[M].北京:国防工业出版社, 2007.

    Li X F. The Principle and Technology of the Satellite-to-ground Laser Communication Links[M]. Beijing: National Defense Industry Press, 2007.

    [3]

    张韵, 王翔, 赵尚弘, 等. Exponentiated Weibull大气湍流下PSK-OFDM机载光链路性能分析[J].光电工程, 2018, 45(2): 170540. doi: 10.12086/oee.2018.170540

    Zhang Y, Wang X, Zhao S H, et al. BER performance for PSK-OFDM optical link over Exponentiated Weibull atmospheric turbulence[J]. Opto-Electronic Engineering, 2018, 45(2): 170540. doi: 10.12086/oee.2018.170540

    [4]

    Tsiftsis T A, Sandalidis H G, Karagiannidis G K, et al. Optical wireless links with spatial diversity over strong atmospheric turbulence channels[J]. IEEE Transactions on Wireless Communications, 2009, 8(2): 951–957. doi: 10.1109/TWC.2009.071318

    [5]

    Khalighi M A, Uysal M. Survey on free space optical communication: a communication theory perspective[J]. IEEE Communications Surveys & Tutorials, 2014, 16(4): 2231–2258. http://cn.bing.com/academic/profile?id=cc45c2505cdd393033da3235eaea81ab&encoded=0&v=paper_preview&mkt=zh-cn

    [6]

    Farid A A, Hranilovic S. Outage capacity optimization for free-space optical links with pointing errors[J]. Journal of Lightwave Technology, 2007, 25(7): 1702–1710. doi: 10.1109/JLT.2007.899174

    [7]

    Jeyarani J, Kumar D S. BER analysis of serial relay-assisted FSO systems over strong atmospheric turbulence[C]//Proceedings of 2015 IEEE International Conference on Signal Processing, Communication and Networking, Chennai, India, 2015: 1–6.

    [8]

    Nistazakis H E, Stassinakis A N, Sheikh Muhammad S, et al. BER estimation for multi-hop RoFSO QAM or PSK OFDM communication systems over gamma gamma or exponentially modeled turbulence channels[J]. Optics & Laser Technology, 2014, 64: 106–112. http://d.old.wanfangdata.com.cn/NSTLQK/NSTL_QKJJ0230007839/

    [9]

    Al-Qahtani F S, El-Malek A H A, Ansari I S, et al. Outage analysis of mixed underlay cognitive RF MIMO and FSO relaying with interference reduction[J]. IEEE Photonics Journal, 2017, 9(2): 7902722. http://cn.bing.com/academic/profile?id=0798f446a43d70add410129455f2eb1f&encoded=0&v=paper_preview&mkt=zh-cn

    [10]

    Jurado-Navas A, Garrido-Balsells J M, Paris J F, et al. A unifying statistical model for atmospheric optical scintillation[M]//Awrejcewicz J. Numerical Simulations of Physical and Engineering Processes. Rijeka, Croatia: InTech, 2011: 181–206.

    [11]

    Yang L, Hasna M O, Gao X Q. Asymptotic BER analysis of FSO with multiple receive apertures over M-distributed turbulence channels with pointing errors[J]. Optics Express, 2014, 22(15): 18238–18245. doi: 10.1364/OE.22.018238

    [12]

    Priyadarshani R, Bhatnagar M R, Ghassemlooy Z, et al. Outage analysis of a SIMO FSO system over an arbitrarily correlated M-distributed channel[J]. IEEE Photonics Technology Letters, 2018, 30(2): 141–144. doi: 10.1109/LPT.2017.2776963

    [13]

    Varotsos G K, Nistazakis H E, Volos C K, et al. FSO links with diversity pointing errors and temporal broadening of the pulses over weak to strong atmospheric turbulence channels[J]. Optik, 2016, 127(6): 3402–3409. doi: 10.1016/j.ijleo.2015.12.060

    [14]

    Awan M S, Horwath L C, Muhammad S S, et al. Characterization of fog and snow attenuations for free-space optical propagation[J]. Journal of Communications, 2009, 4(8): 533–545. http://d.old.wanfangdata.com.cn/OAPaper/oai_doaj-articles_cec046db7bd49a28028e8658f6eaa21f

    [15]

    Popoola W O, Ghassemlooy Z, Allen J I H, et al. Free-space optical communication employing subcarrier modulation and spatial diversity in atmospheric turbulence channel[J]. IET Optoelectronics, 2008, 2(1): 16–23. http://cn.bing.com/academic/profile?id=74fa1aa9ffe6d2f30e9a12c94e329747&encoded=0&v=paper_preview&mkt=zh-cn

    [16]

    Safari M, Uysal M. Relay-assisted free-space optical communication[J]. IEEE Transactions on Wireless Communications, 2008, 7(12): 5441–5449. doi: 10.1109/T-WC.2008.071352

    [17]

    Nistazakis H E, Stassinakis A N, Sandalidis H G, et al. QAM and PSK OFDM RoFSO over M-turbulence induced fading channels[J]. IEEE Photonics Journal, 2015, 7(1): 7900411.

    [18]

    Wolfram function site[EB/OL]. 2019. http://functions.wolfram.com/.

  • 加载中

(7)

(1)

计量
  • 文章访问数:  6623
  • PDF下载数:  2551
  • 施引文献:  0
出版历程
收稿日期:  2019-06-19
修回日期:  2019-09-30
刊出日期:  2020-01-01

目录

/

返回文章
返回