IJBTT

Convolutional Coded On - Off Keying Free - Space Optical Links over Fading Channels

	International Journal of Engineering Trends and Technology (IJETT)
	© 2013 by IJETT Journal
	Volume-4 Issue-5
	Year of Publication : 2013
	Authors : G.Mounika , Ms.K.Sudha

Citation 

G.Mounika , Ms.K.Sudha. "Convolutional Coded On - Off Keying Free - Space Optical Links over Fading Channels". International Journal of Engineering Trends and Technology (IJETT). V4(5):1918-1923 May 2013. ISSN:2231-5381. www.ijettjournal.org. published by seventh sense research group.

Abstract

The performance of Free Space Optical (FSO) systems reduces due to the presence of turbulence and misalignment effects. In this paper, we investigate the error control coding schemes as a candidate solution to mitigate turbulence and misalignment induced fadings over free space optical links. we have investigated for first t ime the error performance for coded on - off keying (OOK) optical wireless communication systems assuming intensity modulation/direct detection(IM/DD) represented by strong turbulence and pointing error effects. Specifically, we consider various combinations of channels assuming the existence of turbulence and/or pointing error effects and derive exact mathematical expressions for the pairwise error probability (PEP). By using this expressions upper bounds on the bit error rate (BER) are obtain using the tran sfer function technique. Then we calculate the error performance by using the pulse position modulation with different fading channels.

References

[1] L. Andrews, R. L. Philips, and C. Y. Ho pen, Laser Beam Scintillation with Applications . SPIE Press, 2001.
[2] D. Kedar and S. Arnon, “Urban optical wireless communications networks: the main challenges and possible solutions," IEEE Commun. Mag. , vol. 42, no. 5, pp. 2 - 7, Feb. 2003.
[3] X. Zhu an d J. M. Kahn, “Performance bounds for coded free - space optical communications through atmospheric turbulence channels," IEEE Trans. Commun. , vol. 51, pp. 1233 - 1239, Aug. 2003.
[4] F. M. Davidson and Y. T. Koh, “Interleaved convolutional coding for the turb ulent atmospheric optical communication channel," IEEE Trans. Commun. , vol. 36, no. 9, pp. 993 - 1003, 1988.
[5] M. Uysal and J. T. Li, “Error performance analysis of coded wireless optical links over atmospheric turbulence channels," in Proc. IEEE Wireless Commun. Netw. Conf. (WCNC) , vol. 4, Mar. 2004, pp. 2405 - 2410.
[6] —— , “BER performance of coded free - space optical links over strong turbulence channels," in Proc. IEEE Veh. Technol. Conf. (VTC spring) , Milan, Italy, May 2004, pp. 168 - 172.
[7] —— , “Error rate performance of coded free - space optical links over gamma - gamma turbulence channels," in Proc. IEEE International Commun. Conf. (ICC’04) , Paris, France, June 2004, pp. 3331 - 3335.
[8] M. Uysal, J. T. Li, and M. Yu, “Error rate performance analysis of coded free - space optical links over gamma - gamma turbulence channels," IEEE Trans. Wireless Commun. , vol. 5, pp. 1229 - 1233, June 2006.
[9] T. Ohtsuki, “Turbo - coded atmospheric optical co mmunication systems," in Proc. IEEE International Commun. Conf. (ICC’02) , NY, USA, May 2002, pp. 2938 - 2942.
[10] J. Chen, D. Huang, and X. Yuan, “Analysis of optical wireless communication system based on a novel turbo code," Optical Eng. , vol. 45, no. 125 006, Dec. 2006.
[11] J. A. Anguita, I. B. Djordjevic, M. A. Neifeld, and B. V. Vasic, “Shannon capacities and error - correction codes for optical atmospheric turbulent channels," J. Optical Netw. , vol. 4, no. 9, pp. 586 - 601, 2005.
[12] A. A. Farid and S. Hr anilovic, “Outage capacity optimization for freespace optical links with pointing errors," J. Lightwave Technol. , vol. 25, pp. 1702 - 1710, July 2007.
[13] M. K. Simon and M. - S. Alouini, Digital Communication over FadingChannels , 2nd edition. Wiley, 2005.
[1 4] I. S. Gradshteyn and I. M. Ryzhik, Table of Integrals, Series, and Products , 6th edition. Academic, 2000. [15] H. G. Sandalidis, “Optimization models for misalignment fading mitigation in optical wireless links," IEEE Commun. Lett. , vol. 12, no. 5, pp. 395 - 397, May 2008.
[16] H. G. Sandalidis, T. A. Tsiftsis, G. K. Karagiannidis, and M. Uysal, “BER performance of FSO links over strong atmospheric turbulence channels with pointing errors," IEEE Commun. Lett. , vol. 12, no. 1, pp. 44 - 46, Jan. 2008.
[17] V. S. Adamchik and O. I. Marichev, “The algorithm for calculating integrals of hypergeometric type functions and its realization in REDUCE system," in Proc. International Conf. Symbolic Algebraic Computation , Tokyo, Japan, 1990, pp. 212 - 224.
[18] J. G. Proaki s, Digital Communications , 3rd edition. McGraw - Hill, 1995

Keywords
Free space optical communications, atmospheric turbulence channel, pairwise error probability, error performa nce analysis.