Journal of the Institute of Electronics Engineers of Korea TC (대한전자공학회논문지TC)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Performance Analysis of Optical CDMA System with Cross-Layer Concept

계층간 교차 개념을 적용한 광 부호분할 다중접속 시스템의 성능 분석

  • Published : 2009.07.25
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Abstract

In this paper, the network performance of a turbo coded optical code division multiple access (CDMA) system with cross-layer, which is between physical and network layers, concept is analyzed and simulated. We consider physical and MAC layers in a cross-layer concept. An intensity-modulated/direct-detection (IM/DD) optical system employing pulse position modulation (PPM) is considered. In order to increase the system performance, turbo codes composed of parallel concatenated convolutional codes (PCCCs) is utilized. The network performance is evaluated in terms of bit error probability (BEP). From the simulation results, it is demonstrated that turbo coding offers considerable coding gain with reasonable encoding and decoding complexity. Also, it is confirmed that the performance of such an optical CDMA network can be substantially improved by increasing e interleaver length and e number of iterations in e decoding process. The results of this paper can be applied to implement the indoor optical wireless LANs.

본 논문에서는 계층간 교차 (Cross-Layer) 개념을 적용하여 터보 (Turbo) 부호화된 광 (Optical) 부호분할 다중접속 (CDMA : Code Division Multiple Access) 시스템의 네트워크 성능을 분석하고 실험하였다. 계층간 교차 개념은 물리 (Physical) 계층과 매체접근제어 (MAC : Medium Access Control) 계층을 고려하였다. 시스템은 펄스위치변조 (PPM : Pulse Position Modulation)를 적용한 강도변조/직접검파 (IM/DD : Intensity Modulation/Direct Detection) 방식의 광 시스템을 고려하였다. 그리고 시스템의 성능을 향상시키기 위해 병렬 연접된 길쌈부호 (PCCC : Parallel Concatenated Convolutional Code)로 이루어진 터보 부호를 사용하였다. 네트워크의 성능은 비트오류확률 (BEP : Bit Error Probabiliy) 측면에서 분석되었다. 모의실험 결과, 터보 부호는 적당한 부호화 및 복호화 복잡도에서 상당한 부호화 이득을 제공하는 것을 확인할 수 있었다. 또한 일정한 부호화율 (Code Rate)에서 인터리버 길이와 복호과정에서의 반복 복호 횟수를 증가시킬수록 시스템 성능이 향상되는 것을 확인하였다.

Keywords

References

  1. J. A. Salehi, "Code division multiple access techniques in optical fiber networks - part I and part II," IEEE Trans. Commun., vol. 37, no. 8, pp. 824-842, Aug. 1989 https://doi.org/10.1109/26.31181
  2. A. J. Mendez, R. M. Gagliardi, H. X. C. Feng, J. P. Heritage, and J. M. Morookian, "Strategies for realizing optical CDMA for dense, high-speed, long span, optical network applications," IEEE J. Lightwave Technol., vol. 18, no. 12, pp. 1685-1696, Dec. 2000 https://doi.org/10.1109/50.908693
  3. S. Galli, R. Menendez, E. Narimanov, and P. Prucnal, 'A novel method for increasing the spectral efficiency of optical CDMA,' IEEE Trans. Commun., vol. 56, no. 12, pp. 2133-2144, Dec. 2008 https://doi.org/10.1109/TCOMM.2008.050640
  4. D. J. G. Mestdagh, Fundamentals of Multiaccess Optical Fiber Networks, Artech house, 1995
  5. P. E. Green, Fiber Optical Networks, Prentice Hall, 1993
  6. I. B. Djordjevic, 'LDPC-coded optical coherent state quantum communications,' IEEE Lett. Photonics Technol., vol. 19, no. 24, pp. 2006-2008, Dec. 2007 https://doi.org/10.1109/LPT.2007.909688
  7. K. K. Wong and T. O'Farrell, 'Spread spectrum techniques for indoor wireless IR communications,' IEEE wireless commun., vol. 10 no. 2, pp. 54-63, Apr. 2003 https://doi.org/10.1109/MWC.2003.1196403
  8. C. Berrou, A. Glavieux, and P. Thitimajshima, 'Near Shannon limit error correcting code: turbo codes,' in Proc. of IEEE ICC'93, pp. 1064, 1070, Geneva, Switzerland, June 1993
  9. E. K. Hall and S. G. Wilson, 'Design and analysis of turbo codes on Rayleigh fading channels,' IEEE J. Select. Areas Commun., vol. 16, no. 2, pp. 160-174, Feb. 1998 https://doi.org/10.1109/49.661105
  10. A. R. Forouzan, M. N. Kenari, and N. Rezaee, "Frame time-hopping patterns in multirate optical CDMA networks using conventional and multicode schemes," IEEE Trans. Commun., vol. 53, no. 5, pp. 863-875, May 2005 https://doi.org/10.1109/TCOMM.2005.847130
  11. C. Argon and S. W. McLaughlin, "Optical OOK-CDMA and PPM-CDMA systems with turbo product codes," IEEE J. Lightwave Technol., vol. 20, no. 9, pp. 1653-1663, Sep. 2002 https://doi.org/10.1109/JLT.2002.802224
  12. G. Bosco, G. Montorsi, and S. Benedetto, "Soft decoding in optical systems," IEEE Trans. Commun., vol. 51, no. 8, pp. 1258-1265, Aug. 2003 https://doi.org/10.1109/TCOMM.2003.815055
  13. J. W. Lee, R. L. Urbanke, and R. E. Blahut, "Trubo codes in binary erasure channel," IEEE Trans. Inform. Theory, vol. 54, no. 4, pp. 1765-1773, Apr. 2008 https://doi.org/10.1109/TIT.2008.917723
  14. A. Mahran and M. Benaissa, "Iterative decoding with a hamming threshold for block turbo codes," IEEE Commun. Lett. vol. 8, no. 9, pp. 567-569, Sep. 2004 https://doi.org/10.1109/LCOMM.2004.835331
  15. F. R. K. Chung, J. A. Salehi, and V. K. Wei, "Optical orthogonal codes: design, analysis and applications," IEEE Trans. Inform. Theory, vol. 35, pp. 595-604, May 1989 https://doi.org/10.1109/18.30982
  16. D. Divsalar, S. Dolinar, and F. Pollara, 'Transfer function bounds on the performance of turbo codes,' The Telecommun. and Data Acquisition Progress Report, 42-122, pp. 44-55, Jet Propulsion Laboratory, Pasadena, CA, Apr. 1995