Rayleigh 페이딩 환경에서 다중레벨 변조방식을 고려한UMM-S/OFDM의 성능분석

Performance Analysis of UMM-S/OFDM with Multi-level Modulation in the Rayleigh Fading Channel

  • 김남수 (한양대학교 전파통신공학) ;
  • 조성호 (한양대학교 정보통신공학)
  • 발행 : 2007.01.31

초록

대각 행렬(unitary matrix)을 이용하여 다중 안테나와 같은 효과를 내기 위한 방법을 USTM (unitary space-time modulation)이라 부르고, 대각행렬 변조(UMM)시에 coherent bandwidth 만큼의 간격(splitting)을 적용한 한 개의 안테나 OFDM시스템(UMM-S/OFDM)을 모델로 삼아 주파수 diversity를 확보하였다. 다중 경로 Rayleigh 페이딩 채널 환경에서 시뮬레이션을 통하여 2개의 송신안테나를 갖는 USTM/OFDM과 한 개의 안테나를 갖는UMM-S/OFDM 시스템의 다중레벨 변조방식을 비교하고, 종래의 다중 OFDM 성능과 UMM-S/OFDM 시스템의 Hz당 부호율 변화에 따른 성능을 비교하였다. 또한, 전송율 변화에 따른 다중 STBC/OFDM과 다중UMM-S/OFDM 시스템의 SNR과 관계를 분석하였으며, SNR을 개선하기 위하여 다중레벨을 적용한 N-ary PSK와 다중레벨 M-ary QAM을 갖는 UMM-S/OFDM 시스템에 대한 성능을 분석하였다.

Unitary matrix modulation (UMM) is investigated in multiple antennas system that is called unitary space-time modulation (USTM). When we consider only diagonal components of UMM with splitting over the coherence bandwidth, the system can obtain frequency diversity in a single antenna system. In Rayleigh fading channel, we compared USTM/OFDM with 2Tx-antenna with UMM-S/OFDM with 1Tx-antenna, conventional multi-level OFDM and UMM-S/OFDM with changing bit rate per Hz. Also, we analyzed SNR for between multi-level modulation STBC/OFDM and multi-level modulation UMM-S/OFDM with changing transmission rate. When it was adaptive multi-level modulation to improve SNR, we did the UMM-S/OFDM system performance analysis of N-ary PSK and M-ary QAM.

키워드

참고문헌

  1. L. Cimini, 'Analysis and simulation of a digital mobile channel using OFDM,' IEEE Trans. on Commun., vol.33, pp.665-675, July 1985 https://doi.org/10.1109/TCOM.1985.1096357
  2. J.A. C. Bingham, 'Multicarrier modulation for data transmission: an idea whose time has come,' IEEE Commun. Mag., vol.28, pp.5-14, May, 1990 https://doi.org/10.1109/35.54342
  3. ETSI ETS 301 958, 'Digital Video Broadcasting (DVB); interaction channel for digital terrestrial television (RCT) incorporating multiple access OFDM,' ETSI, Tech. Rep., March 2002
  4. 'IEEE draft standard for local and metropolitan area network-part 16: Air interface for fixed broadband wireless access systems - medium access control modifications and additional physical layer specifications for 2-11GHz,' IEEE LAN MAN Standards Committee, 2002
  5. I. Koffman and V. Roman, 'Broadband wireless access solutions based on OFDM access in IEEE802.16,' IEEE Commun. Mag., vol. 40, pp. 96-103, April, 2002
  6. V. Tarokh, N. Seshadri, and A.R. Calderbank, 'Space-time codes for high data rate wireless communication: performance criterion and code construction,' IEEE Trans. on Information Theory, vol.44, no.2, pp.744-765, Feb., 1998 https://doi.org/10.1109/18.661517
  7. V. Tarokh, N. Seshadri, and A.R. Calderbank, 'Space-time block coding for wireless communication: performance results,' IEEE J. of Select. Areas Commun., vol.17, no.3, pp.451-460, Mar., 1999 https://doi.org/10.1109/49.753730
  8. V. Tarokh, A. Naguib, N. Seshadri, and A.R. Calderbank, 'Combined array processing and space-time coding,' IEEE Trans. on Information Theory, vol.45, no.2, pp.1121-1128, Feb., 1999 https://doi.org/10.1109/18.761255
  9. G. Raleigh, and J. M. Cioffi, 'Spatio-temporal coding for wireless communication,' IEEE Trans. on Commun., vol.46, no.3, pp.357-366, Mar., 1998 https://doi.org/10.1109/26.662641
  10. S. Fukumoto, M. Sawahashi, and F. Adachi, 'Performance comparison of forward link transmit diversity techniques for W-CDMA mobile radio,' Proc. of PIMRC'99, vol.3, pp.1139-1143, Sept., 1999
  11. S. M. Alamouti, 'A simple transmit diversity technique for wireless communications,' IEEE J. Sel. Areas Commun, vol.16, no.8, pp.1451-1458, Oct., 1998 https://doi.org/10.1109/49.730453
  12. T.L.Marzetta, and B.M. Hochwald, 'Capacity of a mobile multiple-antenna communication link in Rayleigh flat fading,' IEEE Trans. on Information Theory, vol.45, no.1, pp.139-157, Jan., 1999 https://doi.org/10.1109/18.746779
  13. B.M. Hochwald, and T.L.Marzetta, 'Unitary space-time modulation for multi-antenna communications in Rayleigh flat fading,' IEEE Trans. on Information Theory, vol.46, no.2, pp.543-563, Mar., 2000 https://doi.org/10.1109/18.825818
  14. B.M. Hochwald, et.al., 'Systematic design of unitary space-time constellation,' IEEE Trans. on Information Theory, vol.46, no.6, pp.1962-1973, Sept., 2000 https://doi.org/10.1109/18.868472
  15. C. Ahn, and I. Sasase, 'Convolutional coded coherent and differential unitary space-time modulated OFDM with bit interleaving for multiple antennas system,' IEICE Technical Report, SST-47, pp.75-80, October, 2002
  16. C. Ahn, and I. Sasase, 'Convolutional coded coherent and differential unitary space-time modulated OFDM with bit interleaving for multiple antennas system,' proc. of ISA 2003, Malta, Sept., 2003
  17. 김남수, 강환민, 조성호, 'UMM(Unitary Matrix Modulation)을 이용한 LDPC(Low Density Parity Check) 코디드 OFDM 시스템,' 한국통신학회지, 30권 5월호, 2005, pp436-444