전자공학회논문지 (Journal of the Institute of Electronics and Information Engineers)

  • 제50권8호
  • /
  • Pages.28-38
  • /
  • 2013
  • /
  • 2287-5026(pISSN)
  • /
  • 2288-159X(eISSN)
대한전자공학회 (The Institute of Electronics and Information Engineers)
권호 표지
DOI QR코드

DOI QR Code

개선된 터보 등화기의 설계와 성능 평가

Design and Performance Evaluation of Improved Turbo Equalizer

  • An, Changyoung (Department of Electronic Engineering, Chungbuk National University) ;
  • Ryu, Heung-Gyoon (Department of Electronic Engineering, Chungbuk National University)
  • 투고 : 2013.04.01
  • 발행 : 2013.08.15
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

본 논문에서는 단일 반송파 시스템에서 LDPC(low density parity check) 부호와 LMS(least mean square) 알고리즘을 이용한 적응 등화기를 사용한 시스템에서 간단한 계산을 통한 궤환 신호를 생성하여 성능을 향상 시키는 개선된 터보 등화기를 제안한다. LDPC부호는 오류를 정정하는데 있어서 매우 좋은 성능을 보인다. 그러나 LDPC 부호는 열악한 환경에서 좋은 성능을 내기 위하여 긴 패리티 검사행렬을 사용하고 LDPC 부호의 반복을 증가시켜 계산량이 크게 늘어난다. 추가로 성능을 더욱 향상시키기 위해 LDPC 부호 기반의 터보 등화 방법을 사용한다. 이 시스템의 경우 반복횟수의 증가로 계산량이 매우 크게 증가하는 단점이 있다. 이러한 계산량의 증가를 보완하기 위하여 LDPC 부호와 연판정 이후의 신호를 이용하여 적응 등화기를 조절한다. 시뮬레이션 결과 더 적은 계산량으로 LDPC 부호를 사용하고 SISO-MMSE(soft input soft output minimum mean square error)알고리즘 기반인 터보 등화기에 근접하는 성능을 내는 것을 확인하였다.

In this paper, we propose a improved turbo equalizer which generates a feedback signal through a simple calculation to improve performance in single carrier system with the LMS(least mean square) algorithm based equalizer and LDPC(low density parity check) codes. LDPC codes can approach the Shannon limit performance closely. However, computational complexity of LDPC codes is greatly increased by increasing the repetition of the LDPC codes and using a long parity check matrix in harsh environments. Turbo equalization based on LDPC code is used for improvement of system performance. In this system, there is a disadvantage of very large amount of computation due to the increase of the repetition number. To less down the amount of this complicated calculation, The proposed improved turbo equalizer adjusts the adoptive equalizer after the soft decision and the LDPC code. Through the simulation results, it's confirmed that performance of improved turbo equalizer is close to the SISO-MMSE(soft input soft output minimum mean square error) turbo equalizer based on LDPC code with the smaller amount of calculation.

키워드

참고문헌

  1. Zogovic, N., Dimic, G., Bajic, D., "PHY-MAC cross-layer approach to energy-efficiency improvement in low-power communications," 8th International Symposium on Wireless Communication Systems (ISWCS 2011), pp. 402-406, Aachen, Germany, Nov. 2011.
  2. Saad, W., El-Fishawy, N., El-Rabaie, S., Shokair, M., "An efficient designed prototype technique for OFDM PAPR reduction using FPGA," Japan-Egypt Conference on Electronics, Communications and Computers (JEC-ECC 2012), pp. 47-52, Alexandria, Egypt, Mar. 2012.
  3. Qureshi, S.U.H., "Adaptive equalization," Proceedings of the IEEE, vol. 73, no .9, pp. 1349-1387, Sept. 1985. https://doi.org/10.1109/PROC.1985.13298
  4. Pancaldi, F., Vitetta, G.M., Kalbasi, R., Al-Dhahir, N., Uysal, M., Mheidat, H., "Single-carrier frequency domain equalization," Signal Processing Magazine, IEEE , vol. 25, no. 5, pp. 37-56, September 2008.
  5. Do-Hoon Kim, Heugn-Gyoon Ryu, Rahman, T.A., "Analysis and performance evaluation of turbo equalizer for fast equalization in single-carrier system," ICT Convergence (ICTC), 2012 International Conference on, pp. 642-646, Jeju island, Korea, Oct. 2012.
  6. Futaki, H., Ohtsuki, T., "Low-density parity-check (LDPC) coded MIMO systems with iterative turbo decoding," Vehicular Technology Conference 2003. (VTC 2003-Fall), pp. 342-346, Orlando, Florida, USA, Oct. 2003.
  7. D. J. MacKay, "Good error correcting codes based on very sparse matrices", IEEE Trans. Inform. Theory, vol. 45, pp. 399-431, Mar. 1999. https://doi.org/10.1109/18.748992
  8. Richardson, T.J., Urbanke, R.L., "The capacity of low-density parity-check codes under message-passing decoding," Information Theory, IEEE Transactions on, vol. 47, no. 2, pp. 599-618, Feb 2001. https://doi.org/10.1109/18.910577
  9. Po-Hui Yang, Jung-Chieh Chen, Ya-Ting Chan, Ming-Yu Lin, "A simplified addition operation Log-SPA LDPC decoder," The 14th Asia-Pacific Conference on Communications (APCC 2008), pp. 1-4, Tokyo, Japan, Oct. 2008.
  10. Tüchler, M., Koetter, R., Singer, A.C., "Turbo equalization: principles and new results," Communications, IEEE Transactions on, vol. 50, no. 5, pp. 754-767, May 2002. https://doi.org/10.1109/TCOMM.2002.1006557
  11. Fertonani, D., Barbieri, A., Colavolpe, G., "Reduced-Complexity BCJR Algorithm for Turbo Equalization," Communications, IEEE Transactions on, vol. 55, no. 12, pp. 2279-2287, Dec. 2007. https://doi.org/10.1109/TCOMM.2007.910638
  12. Qing. S. T., Dong S. H., "Performance Analysis of DVB-T2 Turbo Equalization with LDPC and MAP Detector," The Korean Society of Broadcast Engineers, vol. 15, no. 5, pp. 665-671, Sep. 2010.
  13. Abu-Surra, S., Ryan, W.E., Divsalar, D., "Asymptotic ensemble enumerators for protograph-based generalized LDPC codes: Computational complexity," Information Theory and Applications Workshop, 2008, pp. 63-65, UCSD, USA, Jan.-Feb. 2008.
  14. Do-Hoon Kim, Heung-Gyoon Ryu, "An efficient blind Pseudo turbo equalizer with CMA and SAGMCMA for single-carrier system," 15th International Conference on Advanced Computing Technologies (ICACT- 2013), pp. 418-422, Korea, Pyeongchang, Jan. 2013.