The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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Decision Feedback Equalizer for DS-UWB Systems

  • 신오순 (숭실대학교 정보통신전자공학부)
  • Published : 2008.05.31
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Abstract

Direct-sequence ultra-wideband(DS-UWB) system is being considered as one of promising transmission technologies for wireless personal area networks(WPANs). Due to relatively low spreading factors and huge bandwidth of transmit signal, a DS-UWB receiver needs to be equipped not only with a rake receiver but also with an equalizer, of which the equalizer is not required for traditional direct-sequence code division multiple access(DS-CDMA) systems. The number of rake fingers is limited in practice, influencing the performance of the subsequent equalizer. In this paper, we derive a decision feedback equalizer(DFE) for DS-UWB systems based on the minimum mean square error(MMSE) criterion, and investigate the impact of various parameters on the DFE performance in realistic scenarios. In particular, we propose an approach to improving the performance of the DFE using additional channel estimates for multipaths not combined in the rake receiver, and discuss how the accuracy of channel estimation affects desirable DFE configuration. Moreover, we present simulation results that show the impact of turbo equalization on the DFE performance.

Keywords

References

  1. D. Porcino and W. Hirt, 'Ultra-wideband radio technology: potential and challenges ahead,' IEEE Commun. Mag., Vol.41, pp.66-74, July 2003
  2. C. R. Aiello and G. D. Rogerson, 'Ultra-wideband wireless systems,' IEEE Microwave Mag., Vol.4, pp.36-47, June 2003 https://doi.org/10.1109/MMW.2003.1201597
  3. FCC, 'First report and order in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems,' ET Docket No. 98-153, FCC 02-48, Apr. 2002
  4. M. Z. Win and R. A. Scholtz, 'Impulse radio: how it works,' IEEE Commun. Lett., Vol.2, pp.36-38, Feb. 1998 https://doi.org/10.1109/4234.660796
  5. IEEE 802.15 high data rate alternative PHY task group 3a for wireless personal area networks, URL: http://www.ieee802.org/15/pub/TG3a.html
  6. R. Fisher et al., 'DS-UWB physical layer submission to 802.15 task group 3a,' IEEE P802.15-04/0137r5, Sept. 2005
  7. C. Razzell et al., 'Multi-band OFDM physical layer proposal update,' IEEE 802.15-04/0220r3, May 2004
  8. O.-S. Shin, S. S. Ghassemzadeh, L. J. Greenstein, and V. Tarokh, 'Performance evaluation of MB-OFDM and DS-UWB systems for wireless personal area networks,' in Proc. IEEE International Conference on Ultra-Wideband 2005, Zurich, Switzerland, pp.214-219, Sept. 2005
  9. A. Parihar, L. Lampe, R. Schober, and C. Leung, 'Equalization for DS-UWB systems-Part I: BPSK modulation,' IEEE Trans. Commun., Vol.55, pp.1164-1173, June 2007 https://doi.org/10.1109/TCOMM.2007.898836
  10. V. D. Trajkovic, P. B. Rapajic, and R. A. Kennedy, 'Turbo DFE algorithm with imperfect decision feedback,' IEEE Signal Proc. Lett., Vol.12, pp.820-823, Dec. 2005
  11. J. G. Proakis, Digital Communications. 4th ed., McGraw-Hill, New York, 2001
  12. J. Foerster, 'Channel modeling sub- committee report final,' IEEE P802.15- 02/490r1, Feb. 2003
  13. A. Saleh and R. Valenzuela, 'A statistical model for indoor multipath propagation,' IEEE J. Select. Areas Commun., Vol.5, pp.128-137, Feb. 1987 https://doi.org/10.1109/JSAC.1987.1146527
  14. UWB channel realizations for CM1-4, available online at ftp://ftp.802wirelessworld. com/15/Archive/2003/Mar03
  15. A. A. D'Amico, U. Mengali, and M. Morelli, 'Channel estimation for uplink of a DS-CDMA system,' IEEE Trans. Wireless Commun., Vol.2, pp.1132-1137, Nov. 2003 https://doi.org/10.1109/TWC.2003.819031