بررسی اثر خطای نشانه روی بر عملکرد یک لینک مخابرات نوری فضای آزاد و ارزیابی آن در مواجه با پدیده‌های جوی

خدادادی, حمیدرضا; قزل ایاغ, محمد حسین; چمن مطلق, ابوالفضل

بررسی اثر خطای نشانه روی بر عملکرد یک لینک مخابرات نوری فضای آزاد و ارزیابی آن در مواجه با پدیده‌های جوی

نوع مقاله : مقاله پژوهشی

نویسندگان

¹ دانشیار،دانشگاه جامع امام حسین (ع)، تهران،ایران

² استادیار،دانشگاه جامع امام حسین (ع)، تهران،ایران

چکیده

سامانه‌های مخابرات نوری فضای آزاد (FSO)، به دلیل داشتن پهنای باند زیاد و امنیت بالا می‌توانند جایگزین مناسبی برای سامانه‌های رادیوئی باشند. شرایط جوی نظیر باران، برف، مه، بادهای قوی و حرکت یا لرزش سکوی فرستنده باعث شکست، انحراف و یا پخش نور ارسالی در مسیر انتشار سیگنال ‌شده و خطاهای نشانه‌روی یا خطای عدم همراستاسازی بین فرستنده و گیرنده را ایجاد می‌کنند. برای کاهش تأثیر این خطاها بر روی عملکرد یک سامانه FSO، از روش‌های مختلفی استفاده می‌شود. در این مقاله بررسی هم‌زمان تضعیف‌های محیط انتشار و تلاطم اتمسفری در کانال گاما - گاما مورد مطالعه قرار گرفته و روابط تحلیلی به‌صورت فرم بسته‌ای برای محاسبه متوسط نرخ خطای بیت(BER) و احتمال وقوع قطع و باوجود خطاهای همراستاسازی آورده شده است. طبق نتایج حاصل از روابط تحلیلی و شبیه‌سازی صورت گرفته، در صورت به‌کارگیری روش-های مناسب کاهش خطاهای نشانه‌روی با داشتن 4 فرستنده و توان ارسالی mW600، یک گیرنده با قطر دهنه اپتیک cm25 ارتباط مخابراتی با نرخ خطای بیت کمتر از 6-10 برای فاصله بین فرستنده و گیرنده km10، در شرایط تلاطم اتمسفری ضعیف (شرایط آب و هوایی مناطق خشک و نیمه‌خشک) امکان پذیر است.

کلیدواژه‌ها

20.1001.1.23224347.1403.12.4.6.0

موضوعات

فناوری های نوین دفاع الکترونیک و سایبری

عنوان مقاله [English]

Investigating the effect of pointing error for FSO link and evaluating its performance in the face of atmospheric phenomena

نویسندگان [English]

Hamidreza Khodadadi ¹
Mohammad Hossein Ghezel Ayagh ¹
A Chamanmotlagh, ²

¹ Associate Professor, Imam Hussein University, Tehran, Iran

² Assistant Professor, Imam Hussein (AS) University, Tehran, Iran

چکیده [English]

Free-Space Optical (FSO) Communication has many advantages such as high bandwidth, high security and can also be a good alternative to radio communication systems. Atmospheric conditions, rain, snow, fog, environmental factors such as strong winds and the movement or vibration of the transmitter platform can cause the transmission light to break or spread, and as a result lead to deviations in the signal propagation path and pointing errors or misalignment errors between the transmitter and receiver. Different methods are used to reduce the effect of weather conditions on pointing errors in FSO. Atmospheric conditions, rain, snow, fog, environmental factors such as strong winds and the movement or vibration of the transmitter platform can cause the transmission light to break or spread, and as a result lead to deviations in the signal propagation path and pointing errors or misalignment errors between the transmitter and receiver. Different methods are used to reduce the effect of weather conditions on pointing errors in open space communications.

In this paper, a model to investigate the FSO attenuation and turbulence effects on its performance is presented and a closed-form expressions for calculating the Bit Error Rate (BER) has been proposed for the gamma-gamma atmospheric turbulence channel and pointing errors.

Because of the atmospheric turbulence effects, in practice, terrestrial FSO links are used for two fixed points over distances up to several kilometers. In this paper using combinational mitigation techniques has shown that an FSO system having 4 transmitters with total 600mW of optical power and a receiver with at least 25cm optical aperture can communicate data, in the week turbulence condition (weather conditions in arid and semi-arid), with a maximum range of 10 km and a BER of better than10-6.

کلیدواژه‌ها [English]

Free Space Optical communication (FSO)
Turbulence
Bit Error Rate (BER)
Pointing error

مراجع

[1] S. A. Al-Gailani et al, “A Survey of Free Space Optics (FSO) Communication Systems, Links, and Networks,” in IEEE Access, vol. 9, pp. 7353-7373, 2021, doi: 10.1109/ACCESS.2020.3048049.

[2] M. A. Khalighi and M. Uysal, “Survey on Free Space Optical Communication: A Communication Theory Perspective,” in IEEE Communications Surveys & Tutorials, vol. 16, no. 4, pp. 2231-2258, Fourthquarter 2014, doi: 10.1109/COMST.2014.2329501.

[3] E.E. Elsayed, B.B. Yousif, “Performance enhancement of hybrid diversity for M-ary modified pulse-position modulation and spatial modulation of MIMO-FSO systems under the atmospheric turbulence effects with geometric spreading,” Opt. Quantum Electron. ,2020, https://doi.org/10.1007/s11082-020-02612-1.

[4] O. Mowlavi, and S. M S. Sadough, “Feedback-based Differential Signaling for 2× 2-FSO System under Atmospheric Turbulence Channel with Pointing Errors,” Journal of Iranian Association of Electrical and Electronics Engineers 18, no. 3, pp.121-133, 2021, ‎ doi: 10.52547/jiaeee.18.3.121.

[5] H. R. Khodadadi, M. H. Ghezel Ayagh, and A. Chaman Motlagh, “ Designing a Free Space Optical communication system and performance evaluation in the face of climate phenomena,” Sayber Defence 4, no. 4 ,pp 89-98, 2016, in persian. dor: https://dor.isc.ac/dor/20.1001.1.23224347.1395.4.4.7.5

[6] M. R. Bhatnagar, “A One Bit Feedback Based Beamforming Scheme for FSO MISO System Over Gamma-Gamma Fading," in IEEE Transactions on Communications, vol. 63, no. 4, pp. 1306-1318, April 2015, doi: 10.1109/TCOMM.2015.2391178.

[7] G.G. Soni, A. Tripathi, A. et al. Mandloi and S. Gupta, “Compensating rain induced impairments in terrestrial FSO links using aperture averaging and receiver diversity," Optical and Quantum Electronics, 51, pp.1-11, 2019, https://doi.org/10.1007/s11082-019-1962-1.

[8] E. E. Elsayed, and B. B. Yousif. , “Performance enhancement of the average spectral efficiency using an aperture averaging and spatial-coherence diversity based on the modified-PPM modulation for MISO FSO links," Optics Communications, 463, p.125463, 2020, https://doi.org/10.1016/j.optcom.2020.125463.

[9] Y. Kaymak, R. Rojas-Cessa, J. Feng, N. Ansari, M. Zhou and T. Zhang, “A Survey on Acquisition, Tracking, and Pointing Mechanisms for Mobile Free-Space Optical Communications,” in IEEE Communications Surveys & Tutorials, vol. 20, no. 2, pp. 1104-1123, Secondquarter 2018, doi: 10.1109/COMST.2018.2804323.

[10] M. R. Bhatnagar and S. Anees, “On the Performance of Alamouti Scheme in Gamma-Gamma Fading FSO Links With Pointing Errors," in IEEE Wireless Communications Letters, vol. 4, no. 1, pp. 94-97, Feb. 2015, doi: 10.1109/LWC.2014.2376958.

[11] L. C. Andrews and R. L. Phillips, “Laser beam propagation through random media.” 2nd Edition, SPIE Optical Engineering Press, 2005.

[12] M. R. Bhatnagar and Z. Ghassemlooy, “Performance analysis of Gamma–Gamma fading FSO MIMO links with pointing errors,” Journal of Lightwave Technology, vol.34,no.9, pp.2158–2169, 2016, doi: 10.1109/JLT.2016.2526053.

[13] M. A. Amirabadi, V. Tabataba Vakili, “A novel hybrid FSO / RF communication system with receive diversity,” Optik, vol 184, pp. 293–298, 2019, , https://doi.org/10.1016/j.ijleo.2019.03.037.

[14] K. Anbarasi, C. Hemanth, R.G. Sangeetha, “A review on channel models in free space optical communication systems,” Optics & Laser Technology, Vol 97, Pages 161-171, 2017, https://doi.org/10.1016/j.optlastec.2017.06.018.

[15] A. Farid and S. Hranilovic, “Outage capacity optimization for free-space optical links with pointing errors,” Lightwave Technology, Journal of, vol. 25, pp. 1702-1710, 2007, doi: 10.1109/JLT.2007.899174.

[16] Djordjevic, Goran T., Milica I. Petkovic, Miodrag Spasic, and Dragan S. Antic, “Outage capacity of FSO link with pointing errors and link blockage,” Optics express 24, no. 1, pp. 219-230, 2016, https://doi.org/10.1364/OE.24.000219.

[17] H. Li-Qiang and W. Zhibin, “A Closed-form Expression for BER of FSO Links over Gamma-Gamma Atmospheric Turbulence Channels with Pointing Errors,” Res. J. Appl. Sci. Eng. Technol. vol. 6 pp. 1272-1275, 2013, doi:10.19026/rjaset.6.3943.

[18] R. Boluda-Ruiz, A. García-Zambrana, B. Castillo-Vázquez, and C. Castillo-Vázquez, “On the capacity of MISO FSO systems over gamma-gamma and misalignment fading channels,” Optics express, vol. 23, pp 22371-22385, 2015, https://doi.org/10.1364/OE.23.022371.

[19] T. Tsiftsis, H. G. Sandalidis, G. K. Karagiannidis, and M. Uysal, “FSO links with spatial diversity over strong atmospheric turbulence channels,” IEEE International Conference on, pp. 5379-5384, 2008, doi:10.1109/ICC.2008.1008.