Skip to content
Licensed Unlicensed Requires Authentication Published online by De Gruyter October 22, 2019

BER Performance Analysis of an Orthogonal FDM Free Space Optical Communication System with Homodyne Optical Receiver over Turbulent Atmospheric Channel

Bobby Barua and S. P. Majumder

Abstract

Atmospheric turbulence induced fading may severely impair free-space optical (FSO) communication systems, affecting the quality of the propagated laser beam and lead to significant performance degradation. Recent research works reveal that performance can be improved by using orthogonal FDM. In this paper, an analytical approach is presented to evaluate the bit error rate performance of an OFDM FSO link with optical intensity modulation and coherent homodyne receiver taking into consideration the effect of strong atmospheric turbulence. The turbulence effect is modeled as gamma-gamma distribution and the performance results are evaluated in terms of average CNR and BER. Power penalty suffered by the system due to the effect of turbulence at a given BER is evaluated for several system parameters viz. link distance, turbulence parameter, local oscillator power etc. It is noticed that effect of turbulence can be significantly reduced by increasing the number of OFDM subcarrier. For example, power penalty for BER of 10–9 at a link distance of 3,600 m is 6 dB when number of subcarrier is 4 and can be reduced to 0.5 dB by increasing the number of subcarrier to 64. In addition, by utilizing coherent optical receiver and synchronous demodulation at the receiving end, we have introduced local oscillator (LO) for both Optical and RF state which have ability to track the signal’s phase changes over time relative to the LO’s phase and helps the system to remain stable.

Acknowledgements

The work is carried out as a part of Ph.D. dissertation in the Dept. of EEE, BUET. The authors would like to acknowledge with gratitude the support provides the Dept. of EEE, BUET.

References

1. Henniger H, Wilfert O. An introduction to free-space optical communications. J Radio Eng. 2010;19:203–12.Search in Google Scholar

2. Sadiku MN, Musa SM. Free space optical communications: an overview. Eur Sci J. 2016;12:55–68.10.19044/esj.2016.v12n9p55Search in Google Scholar

3. Sharma V, Kaur G. Degradation measures in free space optical communication (FSO) and its mitigation techniques – a review. Int J Comput Appl. 2012;55:23–7.10.5120/8719-2585Search in Google Scholar

4. Viswanath A, Kaushal H, Jain VK, Kar S. Evaluation of performance of ground to satellite free space optical link under turbulence conditions for different intensity modulation schemes. Proc. SPIE 8971, Free-Space Laser Communication and Atmospheric Propagation XXVI, vol. 8971, 2014.10.1117/12.2038212Search in Google Scholar

5. Lee IE, Ghassemlooy Z, Ng WP, Khalighi MA. Joint optimization of a partially coherent Gaussian beam for free-space optical communication over turbulent channels with pointing errors. Opt Lett. 2013;38:350–2.10.1364/OL.38.000350Search in Google Scholar PubMed

6. Zedini E, Ansari IS, Alouini MS. On the performance of hybrid line of sight RF and RF-FSO fixed gain dual-hop transmission system. IEEE Global Communication Conference (GLOBECOM), Austin, USA, 2014.10.1109/GLOCOM.2014.7037121Search in Google Scholar

7. Barua B, Majumder SP. Performance analysis of a multiple subcarrier modulated FSO communication system using direct detection optical receiver under the effect of weak atmospheric turbulence. J Opt Commun. 2018;39:1–9.10.1515/joc-2018-0006Search in Google Scholar

8. Cvijetic N, Wang T. WiMAX over free-space optics-evaluating OFDM multi-subcarrier modulation in optical wireless channels. IEEE Sarnoff Symposium, Princeton, USA, 2006:1–4.10.1109/SARNOF.2006.4534760Search in Google Scholar

9. Armstrong J. OFDM for optical communications. IEEE/OSA J Lightwave Technol. 2009;27:189–204.10.1109/JLT.2008.2010061Search in Google Scholar

10. Nistazakis E, Stassinakis AN, Sinanovic S, Popoola WO, Tombras GS. Performance of quadrature amplitude modulation orthogonal frequency division multiplexing based free space optical links with non-linear clipping effect over Gamma-Gamma modeled turbulence channels. IET Optoelectron. 2015;9:269–74.10.1049/iet-opt.2014.0150Search in Google Scholar

11. Nistazakis E, Stassinakis AN, Sandalidis HG, Tombras GS. QAM and PSK OFDM RoFSO over M-turbulence induced fading channels. IEEE Photon J. 2015;7:1.10.1109/JPHOT.2014.2381670Search in Google Scholar

12. Barua B, Majumder SP. Bit error rate analysis of an OFDM subcarrier modulated FSO link with optical intensity modulation and a direct detection receiver. Int J Opt Photon Eng. 2019;4:1–11.Search in Google Scholar

13. Bai F, Su Y, Sato T. Performance evaluation of dual diversity reception base on OFDM RoFSO systems over correlated log-normal fading channel. ITU Kaleidoscope Academic Conf., St Petersburg, Russia, 2014:263–8.10.1109/Kaleidoscope.2014.6858473Search in Google Scholar

14. Sharma V, Kaur G. Modelling of OFDM-ODSB-FSO transmission system under different weather conditions. IEEE Third International Conference on Advance Computing and Communication Technologies (ACCT 2013), 2013:154–7.10.1109/ACCT.2013.37Search in Google Scholar

15. Bekkali A, Naila CB. Transmission analysis of OFDM-based wireless services over turbulent radio-on-FSO links modeled by gamma–gamma distribution. IEEE Photon J. 2010;2:510–20.10.1109/JPHOT.2010.2050306Search in Google Scholar

16. Chaudharya S, Amphawanab A, Nisar K. Realization of free space optics with OFDM under atmospheric turbulence. Optik. 2014;125:5196–8.10.1016/j.ijleo.2014.05.036Search in Google Scholar

17. Sharma V, Sushank. High speed CO-OFDM-FSO transmission system. Optik. 2014;125:1761–3.10.1016/j.ijleo.2013.10.010Search in Google Scholar

18. Chen C, Zhong W, Li X, Wu D. MDPSK based non equalization OFDM for coherent free space optical communication”. IEEE Photon Technol Lett. 2014;26:1617–20.10.1109/LPT.2014.2329133Search in Google Scholar

19. Sharma V, Lumba M, Kaur G. Severe climate sway in coherent CDMA-OSSB-FSO transmission system. Opt Int J Light Electron Opt. 2014;125:5705–7.10.1016/j.ijleo.2014.06.088Search in Google Scholar

20. Andrews LC, Phillips RL, Hopen CY. Aperture averaging of optical scintillations: power fluctuations and the temporal spectrum. Waves Random Media. 2000;10:53–70.10.1088/0959-7174/10/1/305Search in Google Scholar

21. Al-Habash MA, Andrews LC, Phillips RL. Mathematical model for the irradiance probability density function of a laser beam propagating through turbulent media. Opt Eng. 2001;40:1554–62.10.1117/1.1386641Search in Google Scholar

22. Uysal M, Jing L, Meng Y. Error rate performance analysis of coded free-space optical links over gamma-gamma atmospheric turbulence channels. IEEE Trans Wireless Commun. 2006;5:1229–33.10.1109/TWC.2006.1638639Search in Google Scholar

23. Kashani MA, Uysal M, Kavehrad M. An ovel statistical channel model of turbulence Induced fading in free space optical systems. IEEE/OSA J Lightwave Technol. 2015;33:2303–12.10.1109/JLT.2015.2410695Search in Google Scholar

24. Tang X, Rajbhandari S, Popoola WO, Ghassemlooy Z, Muhammad SS, Leitgeb E, et al. Performance of BPSK subcarrier intensity modulation free-space optical communications using a lognormal atmospheric turbulence model IEEE Conference, 2010:17–20.10.1109/SOPO.2010.5504014Search in Google Scholar

25. NavasJ, BalsellsG, ParisJM, Puerta NotarioJF. A unifying statistical model for atmospheric optical scintillation. invited chapter in numerical simulations of physical and engineering processes. Rijeka, 2011.Search in Google Scholar

Received: 2019-08-19
Accepted: 2019-10-07
Published Online: 2019-10-22

© 2019 Walter de Gruyter GmbH, Berlin/Boston

Scroll Up Arrow