Performance of a Modified Multicarrier Direct Sequence CDMA System

  • 발행 : 1997.04.30

초록

In this paper, we present an improved multicarrier direct sequence (DS) code division multiple access (CDMA) scheme by modifying the system originally proposed by Kondo and Milstein [13]. In this modified system, different spreading sequences multiplied by a data sequence modulate different carriers. This is to prevent the multiple access capability from reducing when the fading characteristics of different carrier frequencies are highly correlated. We have derived a formula which determines the mean values of the relative received signal strength in a single carrier DS CDMA rake system and in a multicarrier DS-CDMA system. We present results on the comparison of the bit error rate (BER) performance of the two systems including the effect of correlation between fading characteristics of different frequencies under various multipath fading conditions. The results indicate that with 50 users the modified multicarrier DS CDMA system can achieve an uncoded irreducible BER of $1.7{\times}10^{-3}$ with an average received signal-to-noise ratio per bit of 10dB, which is better that $3.0{\times}10^{-3}$ achieved by the single carrier DS CDMA rake system, and also show that if multicarrier CDMA system is used with respect to single carrier CDMA system, the SNR gain is up to 4.5 dB for the uncode BER of $10^{-3}$ being achieved.

키워드

참고문헌

  1. IEEE J. Select. Areas Commun. v.10 no.4 On the Feasibility of a CDMA overlay for personal communications networks Milstein, L.B.;Schilling, D.L.;Pickholtz, R.L.;Erceg, V.;Kullback, M.;Kanterakis, E.G.;Fishman, D.S.;Biederman, W.H.;Salerno, D.C.
  2. IEEE J. Select. Areas Commun. v.12 no.5 Comparison of hybrid FDMA/COMA systems in frequency selective Rayleigh fading Eng, T.;Milstein, L.B.
  3. IEEE Personal Commun. v.2 no.5 Validating a complex system in a complex environment: realtime testbed for assessing a CDMA-based system Steefansson, T.;Allkins, M.
  4. TR46.3.3/T1P1.4, Wideband CDMA system for wideband spread spectrum digital 1.80-1.99 GHz PCS microcellular system
  5. IEEE Commun. Mag. v.28 no.5 Multicarrier modulation for data transmission: an idea whose time has come Bingham, J.A.C.
  6. Proc. PIMRC '93 Multi-carrier CDMA in indoor wireless radio networks Yee, N.;Linnartz, J.P.;Fettweis, G.
  7. Proc. VTC '94 Controlled equalization on multi-carrier CDMA in an indoor Rician fading channel Yee, N.;Linnartz, J.P.
  8. Proc. PIMRC '93 On the performance of convolutionally-coded CDMA/OFDM for mobile communication system Fazel, K.;Papke, L.
  9. Proc. ICUPC '93 Performance of CDMA/OFDM for mobile communication system Fazel, K.
  10. Proc. GLOBECOM '93 Orthogonal multicarrier technique applied to direct sequence spread spectrum CDMA systems Chouly, A.;Brajal, A.;Jourdan, S.
  11. Proc. VTC '94 Multicarrier CDMA system with cochannel interference cancellation Kondo, S.;Milstein, L.B.
  12. Proc. MILCOM '94 Multicarrier DS CDMA systems in the presence of partial band interference Kondo, S.;Milstein, L.B.
  13. IEEE Trans. on Commun. v.44 no.2 Performance of Multicarrier DS CDMA Systems Kondo, S.;Milstein, L.B.
  14. Proc. ICUPC '94 Narrow-band interference rejection in orthogonal multi-carrier spread-spectrum communications Fazel, K.
  15. Proc. VTC '96 Effect of correlation between subcarries of an MCM/DSSS communication system Ziemer, R.E.;Nadauda, N.
  16. Digital Communications Proakis, J.
  17. Communication Systems and Techniques Schwarz, M.;Bennett, W.R.;Stein, S.
  18. IEEE Trans. Commun v.COM-29 no.7 An orthogonally multiplexed QAM system using the discrete fourier transform Botaro Hirosaki