The Journal of the Korea institute of electronic communication sciences (한국전자통신학회논문지)

Korea Institute of Electronic Communication Science (한국전자통신학회)
권호 표지
DOI QR코드

DOI QR Code

Channel Estimation Based on LMS Algorithm for MIMO-OFDM System

MIMO-OFDM을 위한 LMS 알고리즘 기반의 채널추정

  • 황석승 (조선대학교 메카트로닉스공학과)
  • Received : 20120631
  • Accepted : 2012.12.10
  • Published : 2012.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

MIMO-OFDM which is one of core techniques for the high-speed mobile communication system requires the efficient channel estimation method with low estimation error and computational complexity, for accurately receiving data. In this paper, we propose a channel estimation algorithm with low channel estimation error comparing with LS which is primarily employed to the MIMO-OFDM system, and with low computational complexity comparing with MMSE. The proposed algorithm estimates channel vectors based on the LMS adaptive algorithm in the time domain, and the estimated channel vector is sent to the detector after FFT. We also suggest a preamble architecture for the proposed MIMO-OFDM channel estimation algorithm. The computer simulation example is provided to illustrate the performance of the proposed algorithm.

고속 이동통신 시스템의 핵심 기술인 다중입력 다중출력(MIMO; Multi-Input Multi-Output) 직교주파수분할(OFDM ; Orthogonal Frequency Division Multiplexing) 기술은 신뢰성 있는 데이터 수신을 위하여 낮은 추정 오차와 복잡도를 가지는 효과적인 채널추정 기법을 필요로 한다. 본 논문은 MIMO-OFDM 통신시스템에서 주로 사용되어 왔던 LS(Least Square)와 같은 기존의 채널추정 방식에 비해 낮은 채널추정 오차를 가지면서, MMSE(Minimum Mean Square Error) 기반의 채널추정 방식과는 유사한 추정 오차를 가지고 복잡도는 MMSE보다 월등히 낮은 채널추정 기법과 이를 위한 프리앰블(preamble) 파일럿 구조를 제안한다. 제안된 방식은 시간영역에서 LMS (Least Mean Square) 적응 알고리즘을 기반으로 채널을 추정하고, 추정된 채널벡터는 FFT(Fast Fourier Transform)를 거쳐 검파기로 보내진다. 컴퓨터 시뮬레이션을 통해 제안된 MIMO-OFDM 채널추정 방식의 성능을 확인한다.

Keywords

References

  1. Y. Jung, J. Him, S. L, H. Y, and J Kim, "Design and implementation of MIMO-OFDM baseband processor for high-speed sireless LANS", IEEE Trans. on Circuit and Systems-II: Express Briefs, Vol. 545, No. 7, pp. 631-635, July 2007.
  2. 박기식, "페이딩 채널에서 MMSE-OSUC 수신기를 적용한 MIMO 시스템의 성능 분석, 한국전자통신학회논문지, 6권, 5호, pp. 732-729, 2011.
  3. 김성권, "저전력 OFDM 모뎀 구현을 위한 IVC 설계", 한국전자통신학회논문지, 3권, 2호, pp. 90-96, 2008.
  4. W.G. Jeon, K.H. Paik, and Y.S. Cho, "An Efficient Channel Estimation Technique for OFDM Systems with transmitter diversity", IEICE Trans. on Communications, Vol. E84-B, pp. 967-974, April 2001.
  5. Y. Li, "Simplified Channel Estimation for OFDM Systems with Multiple Transmit antennas", IEEE Trans. on Wireless Communications, Vol. 1, pp. 67-75, Jan. 2004.
  6. S. Zhou, B. Muquet, and G.G. Giannakis, "Subspace-Based (Semi-) Blind Channel Estimation for Block Precoded Space-Time OFDM". IEEE Trans. on Signal Processing, Vol. 50, pp. 1215-1228, May 2002. https://doi.org/10.1109/78.995088
  7. Sinem Coleri, Mustafa Ergen, Anuj Puri, and Ahmad Bahai, "Channel Estimation Techniques Based on Pilot Arrangement in OFDM Systems", IEEE Trans. on Broadcasting, Vol. 48, pp. 223-229, Sept. 2004.
  8. B. Widrow and S. D. Stearns, Adaptive Signal Processing. Englewood Cliffs, NJ : Prentice-Hall, 1985.
  9. 황석승, "적응 알고리즘을 이용한 MIMO-OFDM 통신환경에서의 채널추정 기법", 한국전자통신학회 2009년 춘계 종합학술대회, 3권, 1호, pp. 376-379, 2009.
  10. S. H. Muller and J. B. Huber, "OFDM with reduced peak-to-average power ratio of multicarrier modulation by selected mapping", Elec. Lett., Vol. 32, No. 22, pp. 2056-2057, Oct. 1996. https://doi.org/10.1049/el:19961384
  11. C. Yin, G. Wen, and Z. Feng, "Simulation research of 802.11n channel model D in NS2", In Proceedings of Computer Science and Information Technology (ICCSIT), 2010 3rd IEEE International Conference, Vol. 7, pp. 530-533, July, 2010
  12. A. V. Oppenheim and R. W. Schafer, Discrete-Time Signal Processing(3rd Edition), Englewood Cliffs, NJ : Prentice Hall Signal Processing, 2009.