수신 신호 상관을 고려한 OFDM 다중 안테나 시스템의 채널 용량 : 2X2 안테나의 경우

Channel Capacity of OFDM-Based Multiple Antenna Systems with Correlated Signals : 2X2 Antenna Case

  • Choi Jae-Ha (Department of Electronic Engineering, Cheongju University) ;
  • Jang Ju-Hyuk (Department of Electronic Engineering, Cheongju University) ;
  • Shin Heui-young (Department of Electronic Engineering, Cheongju University) ;
  • Kim Nam-Soo (Department of Electronic Engineering, Cheongju University)
  • 발행 : 2004.10.01

초록

본 논문은 주파수 선택적 레일레이 페이딩(Frequency selective Rayleigh fading) 환경 하에서 수신 신호들 간에 상관이 존재할 때, OFDM(Othogonal Frequency Division Multiplexing) 다중 안테나 시스템의 채널 용량을 연구하였다. 송, 수신안테나를 각각 두 개 사용하였을 때, 채널 용량을 상관 계수의 함수로 closed-form 형태로 유도하였고, 각 안테나 당 평균수신 신호 전력이 동일할 때와 동일하지 않을 때 채널 용량에 미치는 영향을 분석하였다. 분석 결과 수신 신호의 상관 계수가 증가할수록 채널 용량이 감소하였고, 수신 신호 상관 계수가 약 0.7보다 클 때 채널 용량은 급격히 감소하였다. 그리고 각 안테나 당 평균 수신 신호 전력이 동일할 때 채널 용량은 최대가 됨을 알 수 있었다.

This study examines the channel capacity of a multiple antenna system based on OFDM(Othogonal Frequency Division Multiplexing) when there are correlations among received signals in the frequency selective Rayleigh fading. As for a case that two transmitting and two receiving antennas are used, the channel capacity is derived as a function of correlation in a closed-form and the effect on channel capacity is analyzed when the mean value of the of received signal power is identical/ non-identical between the two receiving antennas. Analytical results show that the channel capacity decreases with the correlation coefficient of the received signals, and the decreasing rate is accelerated when the correlation coefficient of the received signals is greater than 0.7. In addition, the channel capacity reaches its peak when the received mean signal power of each branch is identical.

키워드

참고문헌

  1. R. Van Nee, R. Prasad, OFDM for Wireless Multimedia Communications, Artech House, 2000
  2. L. Hanzo, M. Munster, B. 1. Choi and T. Keller, OFDM andMC-CDMA for Broadband Multi-User Communications, WLANs and Broadcasting, John Wiley & Sons, Inc., 2003
  3. Ozgur Oyman, Rohit U. Nabar, Helmut Bolcskei and Arogyaswarni 1. Paulraj, 'Characterizing the statistical properties of mutual information in MIMO channels', IEEE Transactions on Signal Processing, vol. 51, no. 11, pp. 2784-2795, Nov. 2003 https://doi.org/10.1109/TSP.2003.818153
  4. G. 1. Foschini, "Layered space-time architecture for wireless communication in a fading environment when using multi-element when using multielement antennas", Bell Labs Tech. J., vol. I, no. 2, pp. 41-59, Aug. 1996 https://doi.org/10.1002/bltj.2015
  5. G. 1. Foschini, M. 1. Gans, 'On limits of wireless communications in a fading environment when using multiple antennas', Wireless Personal Communications, vol. 6, no. 3, pp. 311-335, Mar. 1998 https://doi.org/10.1023/A:1008889222784
  6. R. B. Ertel, Paulo Cardieri, Kevin W. Sowerby, Theodore S. Rappaport and Jeffrey H. Reed, 'Overview of spatial channel models for antenna array communication systems", IEEE Personal Communications, vol. 5, Issue : 1, pp. 10-22, Feb. 1998 https://doi.org/10.1109/98.656151
  7. Arogyaswami Paulraj, Rohit Nabar and Dhananjay Gore, Introduction to Space-Time Wireless Communications, Cambridge, 2003
  8. Tai-Lai Tung, Kung Yao, 'Channel estimation and optimal power al1ocation for a multiple-antenna OFDM system', Eurasip Journal on Applied Signal Processing, vol. 2002, Issue : 3, pp. 330-339, Mar. 2002 https://doi.org/10.1155/S1110865702000689
  9. Helmut Bolcskei, David Gesbert and Arogyaswami 1. Paulraj, 'On the capacity of OFDM-based spatial multiplexing systems', IEEE Transactions on Communications, vol. 50, no. 2, pp. 225-234, Feb. 2002 https://doi.org/10.1109/26.983319
  10. Jibing Wang, Kung Yao, 'Capacity scaling in OFDM based spatial multiplexing systems', IEEE Vehicular Technology Conference, vol. I, pp. 28-32, Sep. 2002
  11. J. Choi, 1. Yuan, P. Rapajic and M. Patwary, 'A study on MIMO-OFDM based space-time technology for high speed packet transmission', Technical Report, The University of New South Wales Sydney Australia, Jan. 2003
  12. S. L. Loyka, 'Channel capacity of two-antenna BLAST architecture', lEE Electronics Letters, vol. 35, no. 17, pp. 1421-1422, Aug. 1999 https://doi.org/10.1049/el:19990987
  13. Steven M. Kay, Fundamentals of Statistical Signal Processing, Volume II Detection Theory, Prentice-Hall PTR Prentice-Hall, Inc., 1998