On the Performance of Blind Chip Rate Estimation in Multi-Rate CDMA Transmissions Using Multi-Rate Sampling in Slow Flat Fading Channels

Affiliation(s)

School of Electrical Engineering, Iran University of Science and Technology, Tehran, Iran.

School of Electrical Engineering, Iran University of Science and Technology, Tehran, Iran.

ABSTRACT

This paper considers blind chip rate estimation of DS-SS signals in multi-rate and multi-user DS-CDMA systems over channels having slow flat Rayleigh fading plus additive white Gaussian noise. Channel impulse response is estimated by a subspace method, and then the chip rate of each signal is estimated using zero crossing of estimated differential channel impulse response. For chip rate estimation of each user, an algorithm which uses weighted zero-crossing ratio is proposed. Maximum value of the weighted zero crossing ratio takes place in the Nyquist rate sampling frequency, which equals to the twice of the chip rate. Furthermore, bit time of each user is estimated using fluctuations of autocorrelation estimators. Since code length of each user can be obtained using bit time and chip time ratio. Fading channels reduce reliability factor of the proposed algo-rithm. To overcome this problem, a receiver with multiple antennas is proposed, and the reliability factor of the proposed algorithm is analyzed over both spatially correlated and independent fading channels.

This paper considers blind chip rate estimation of DS-SS signals in multi-rate and multi-user DS-CDMA systems over channels having slow flat Rayleigh fading plus additive white Gaussian noise. Channel impulse response is estimated by a subspace method, and then the chip rate of each signal is estimated using zero crossing of estimated differential channel impulse response. For chip rate estimation of each user, an algorithm which uses weighted zero-crossing ratio is proposed. Maximum value of the weighted zero crossing ratio takes place in the Nyquist rate sampling frequency, which equals to the twice of the chip rate. Furthermore, bit time of each user is estimated using fluctuations of autocorrelation estimators. Since code length of each user can be obtained using bit time and chip time ratio. Fading channels reduce reliability factor of the proposed algo-rithm. To overcome this problem, a receiver with multiple antennas is proposed, and the reliability factor of the proposed algorithm is analyzed over both spatially correlated and independent fading channels.

Cite this paper

nullS. GHAVAMI and B. ABOLHASSANI, "On the Performance of Blind Chip Rate Estimation in Multi-Rate CDMA Transmissions Using Multi-Rate Sampling in Slow Flat Fading Channels,"*Wireless Sensor Network*, Vol. 1 No. 2, 2009, pp. 69-75. doi: 10.4236/wsn.2009.12011.

nullS. GHAVAMI and B. ABOLHASSANI, "On the Performance of Blind Chip Rate Estimation in Multi-Rate CDMA Transmissions Using Multi-Rate Sampling in Slow Flat Fading Channels,"

References

[1] E. Dahlman, P. Beming, J. Knutsson, F. Ovesjo, M. Persson, and C. Roobol, “WCDMA-the radio interface for future mobile multimedia communications,” IEEE Transactions on Vehicular Technology, Vol. 47, pp. 1105–1118, November 1998.

[2] P. Taaghol, B. G. Evans, E. Buracchini, G. De Gaudinaro, Joon Ho Lee, and Chung Gu Kang, “Satellite UMTS/ IMT2000 W-CDMA air interfaces,” IEEE Communica-tions Magazine, Vol. 37, pp. 116–126, September 1999.

[3] Z. Zhang, L. Li, and X. Xiao; “Carrier frequency and chip rate estimation based on cyclic spectral density of MPSK signals,” in Proceedings of Communications, Circuits and Systems Conference, Vol. 2, pp. 859 –862, June 2004.

[4] W. J. Ma, S. M. Yang, W. Ren, Z. H. Xue, and W. M. Li, “Spectral correlation function in low SNR environment,” in Proceedings of Radio Science Asia-Pacific Conference, pp. 197–200, August 2004.

[5] Y. X. Li, M. Yi, Q. Yang, X. C. Xiao, and H. M. Tai, “Low SNR BPSK signal chip rate estimation using a wavelet based spectral correlation algorithm,” in Pro-ceedings of Circuit and Systems Conference, Vol. 3, pp. 247–249, August 2002.

[6] P. G. Turner, R. Hewitt, and D. J. Purle, “Chip-rate proc-essing for software defined radios,” in Proceedings of 3G Mobile Communication Technologies, pp. 292–296, March 2001.

[7] Y. Jin and H. B. Ji, “A cyclic-cumulant based method for DS-SS signal detection and parameter estimation,” in Proceedings of Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications Con-ference, Vol. 2, pp. 966–969, August 2005.

[8] S. Ghavami and B. Abolhassani, “Blind chip time estima-tion in multirate CDMA transmissions using multirate sampling in slow flat fading channels,” in the Proceed-ings of IEEE-ICCS08, pp. 1344–1348, November 2008.

[9] C. N. Nzéza, R. Gautier, and G. Burel, “Parallel blind multiuser synchronization and sequence estimation in multirate CDMA transmissions,” in Proceedings of IEEE - ACSSC, pp. 2157–2161, November 2006.

[10] C. N. Nzéza, R. Gautier, and G. Burel, “Blind multiuser detection in multirate CDMA transmissions using fluc-tuations of correlation estimators,” in Proceedings of IEEE - Globecom, pp. 1–5, November 2006.

[11] Q. T. Zhang, “Maximal-ratio combining over Nakagami fading channels with an arbitrary branch covariance ma-trix,” IEEE Transactions on Vehicular Technology, Vol. 48, No. 4, pp.1141–1150, July 1999.

[12] W. C. Lee, “Mobile communications: Design fundamentals,” 2nd Edition, New York, Wiley, pp. 202–211, 1993.

[1] E. Dahlman, P. Beming, J. Knutsson, F. Ovesjo, M. Persson, and C. Roobol, “WCDMA-the radio interface for future mobile multimedia communications,” IEEE Transactions on Vehicular Technology, Vol. 47, pp. 1105–1118, November 1998.

[2] P. Taaghol, B. G. Evans, E. Buracchini, G. De Gaudinaro, Joon Ho Lee, and Chung Gu Kang, “Satellite UMTS/ IMT2000 W-CDMA air interfaces,” IEEE Communica-tions Magazine, Vol. 37, pp. 116–126, September 1999.

[3] Z. Zhang, L. Li, and X. Xiao; “Carrier frequency and chip rate estimation based on cyclic spectral density of MPSK signals,” in Proceedings of Communications, Circuits and Systems Conference, Vol. 2, pp. 859 –862, June 2004.

[4] W. J. Ma, S. M. Yang, W. Ren, Z. H. Xue, and W. M. Li, “Spectral correlation function in low SNR environment,” in Proceedings of Radio Science Asia-Pacific Conference, pp. 197–200, August 2004.

[5] Y. X. Li, M. Yi, Q. Yang, X. C. Xiao, and H. M. Tai, “Low SNR BPSK signal chip rate estimation using a wavelet based spectral correlation algorithm,” in Pro-ceedings of Circuit and Systems Conference, Vol. 3, pp. 247–249, August 2002.

[6] P. G. Turner, R. Hewitt, and D. J. Purle, “Chip-rate proc-essing for software defined radios,” in Proceedings of 3G Mobile Communication Technologies, pp. 292–296, March 2001.

[7] Y. Jin and H. B. Ji, “A cyclic-cumulant based method for DS-SS signal detection and parameter estimation,” in Proceedings of Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications Con-ference, Vol. 2, pp. 966–969, August 2005.

[8] S. Ghavami and B. Abolhassani, “Blind chip time estima-tion in multirate CDMA transmissions using multirate sampling in slow flat fading channels,” in the Proceed-ings of IEEE-ICCS08, pp. 1344–1348, November 2008.

[9] C. N. Nzéza, R. Gautier, and G. Burel, “Parallel blind multiuser synchronization and sequence estimation in multirate CDMA transmissions,” in Proceedings of IEEE - ACSSC, pp. 2157–2161, November 2006.

[10] C. N. Nzéza, R. Gautier, and G. Burel, “Blind multiuser detection in multirate CDMA transmissions using fluc-tuations of correlation estimators,” in Proceedings of IEEE - Globecom, pp. 1–5, November 2006.

[11] Q. T. Zhang, “Maximal-ratio combining over Nakagami fading channels with an arbitrary branch covariance ma-trix,” IEEE Transactions on Vehicular Technology, Vol. 48, No. 4, pp.1141–1150, July 1999.

[12] W. C. Lee, “Mobile communications: Design fundamentals,” 2nd Edition, New York, Wiley, pp. 202–211, 1993.