System Performance Comparison of Turbo and Trellis Coded Optical CDMA Systems

Authors: M. Kulkarni, R. K. Sinha, D. R. Bhaskar

Abstract:

In this paper, we have compared the performance of a Turbo and Trellis coded optical code division multiple access (OCDMA) system. The comparison of the two codes has been accomplished by employing optical orthogonal codes (OOCs). The Bit Error Rate (BER) performances have been compared by varying the code weights of address codes employed by the system. We have considered the effects of optical multiple access interference (OMAI), thermal noise and avalanche photodiode (APD) detector noise. Analysis has been carried out for the system with and without double optical hard limiter (DHL). From the simulation results it is observed that a better and distinct comparison can be drawn between the performance of Trellis and Turbo coded systems, at lower code weights of optical orthogonal codes for a fixed number of users. The BER performance of the Turbo coded system is found to be better than the Trellis coded system for all code weights that have been considered for the simulation. Nevertheless, the Trellis coded OCDMA system is found to be better than the uncoded OCDMA system. Trellis coded OCDMA can be used in systems where decoding time has to be kept low, bandwidth is limited and high reliability is not a crucial factor as in local area networks. Also the system hardware is less complex in comparison to the Turbo coded system. Trellis coded OCDMA system can be used without significant modification of the existing chipsets. Turbo-coded OCDMA can however be employed in systems where high reliability is needed and bandwidth is not a limiting factor.

Keywords: avalanche photodiode, optical code division multipleaccess, optical multiple access interference, Trellis codedmodulation, Turbo code

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1077471

References:

[1] F. R .K Chung, J. A Salehi and V. K. Wei ,"Optical Orthogonal codes: Design , Analysis and Applications", IEEE Trans Inform. Theory, vol. IT-35, pp. 595-604, May 1989.
[2] J. A. Salehi, "Code division multiple access techniques in optical fiber networks -Part 1: Fundamental Principles" , IEEE Trans. Commun , vol. COM-37 , pp. 824-833, Aug 1989
[3] J. A. Salehi and C. A Brackett, " Code division multiple access techniques in optical fiber networks - Part 2: System Performance analysis", IEEE Trans. Commun, vol. COM-37, pp. 834-842, Aug 1989
[4] C. Berrou and A. Glavieux, "Near optimum error correcting coding and decoding: Turbo Codes", IEEE Trans Commun, vol. COM-44, pp.1261- 1271, Oct 1996.
[5] J. G Zhang: "Performance "Improvement of fiber optic code division multiple access systems by using error correction codes", IEE proceedings, online no 19971454,1997.
[6] Maw-Yang Liu and Hen - Wai Tsao, "Trellis Coded asynchronous optical CDMA systems" IEEE Journal of Light wave Tech., vol. 19, no2 Feb 2001
[7] T. Ohtsuki, "Performance analysis of direct detection optical asynchronous CDMA systems with double optical hard limiters", IEEE Journal of Light wave Tech., vol.15, pp.452-457, Mar 1997
[8] H. M. Kwon, "Optical orthogonal code-division multiple access system - Part 1: APD noise and thermal noise," IEEE Trans. Commun., vol. 42, pp. 2470-2479, July 1994.
[9] C. E. Shannon, "A mathematical theory of communication," Bell Sys. Tech. J., vol. 27, pp. 379-423 and 623-656, 1948.
[10] C. Berrou, A. Glavieux, and P. Thitimajshima,. "Near Shannon limit error-correcting coding and decoding: turbo-codes", Proc. IEEE ICC'93, pp. 1064-1070, Geneva, Switzerland, May 1993.
[11] D. Divsalar and F. Pollara, " Turbo codes for deep space communications," TDA Progress Report 42-120, pp. 29-39, Feb. 1995.
[12] S. Benedetto and G. Montorsi, "Unveiling turbo codes: some results on parallel concatenated schemes," IEEE Trans. Inform. Theory, vol. 42, no. 2, pp. 409-428, Mar. 1996.
[13] S. Benedetto, G. Montorsi, D. Divsalar, and F. Pollara, "Soft-output decoding algorithms in iterative decoding of turbo codes," TDA Progress Report 42-124, pp. 63-83, Feb. 1996.
[14] S. Benedetto, D. Divsalar, G. Montorsi, and F. Pollara, "A soft-input soft-output maximum a posteriori (map) module to decode parallel and serial concatenated codes," TDA Progress Report 42-127, pp. 1-20, Nov.1996.
[15] S. Benedetto, D. Divsalar, G. Montorsi, and F. Pollara, \Serial concatenation of interleaved codes: performance analysis, design, and iterative decoding," IEEE Tran Inform. Theory, vol. 44, no. 3, pp. 909- 926, May 1998.
[16] B. Vucetic and J. Yuan, Turbo Codes, Kluwer Academic Publishers, 2000.
[17] J. Proakis, Digital Communications, 4th ed., McGraw-Hill, New York, 2001.
[18] S. Haykins, Communication Systems, 4th ed., John Wiley & Sons, 2003.