A multiuser detection scheme with pilot symbol-aided channel estimation for synchronous CDMA systems

A decorrelating decision-feedback detector is considered for multiuser detection for frequency-selective synchronous CDMA channels. This detector operates on the outputs of matched filters which are matched to the original code waveforms of the system. A maximum likelihood estimation to estimate parameters of the decorrelating decision-feedback filters is proposed and derived. The estimation method is based on inserting known training sequences into the information data by all users simultaneously. To achieve minimum mean-square-error (MMSE) in estimation, a criterion for how to select the training sequences is suggested. The estimation method requires a matrix inversion at the end of each training period. The simulation results show some degradations in system performance compared to the case where the perfect knowledge of the channel is assumed. This degradation is clearly due to errors in the channel estimation.

[1]  Charles R. Johnson,et al.  Matrix analysis , 1985, Statistical Inference for Engineers and Data Scientists.

[2]  S. Kay.  Fundamentals of statistical signal processing: estimation theory , 1993 .

[3]  Zoran Zvonar,et al.  Suboptimal multiuser detector for frequency-selective Rayleigh fading synchronous CDMA channels , 1995, IEEE Trans. Commun..

[4]  Sergio Verdú,et al.  Linear multiuser detectors for synchronous code-division multiple-access channels , 1989, IEEE Trans. Inf. Theory.

[5]  Alexandra Duel-Hallen,et al.  Decorrelating decision-feedback multiuser detector for synchronous code-division multiple-access channel , 1993, IEEE Trans. Commun..

[6]  M. Fattouche,et al.  Symbol-aided channel estimation and multiuser detection for CDMA systems using a decorrelating detector , 1997, 1997 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, PACRIM. 10 Years Networking the Pacific Rim, 1987-1997.

[7]  Behnaam Aazhang,et al.  Multistage detection in asynchronous code-division multiple-access communications , 1990, IEEE Trans. Commun..

[8]  Mahesh K. Varanasi,et al.  Multiuser detectors for synchronous CDMA communication over non-selective Rician fading channels , 1994, IEEE Trans. Commun..

[9]  Mahesh K. Varanasi,et al.  Near-optimum detection in synchronous code-division multiple-access systems , 1991, IEEE Trans. Commun..

[10]  T. Matsumoto,et al.  Joint decorrelating multiuser detection and channel estimation in asynchronous CDMA mobile communications channels , 1995 .

[11]  H. Zaghloul,et al.  Combined Multiuser Detection and Diversity Reception for Wireless CDMA Systems , 1996 .

[12]  Zoran Zvonar,et al.  Multiuser detection in single-path fading channels , 1994, IEEE Trans. Commun..

[13]  Mahesh K. Varanasi,et al.  Optimum diversity combiner based multiuser detection for time-dispersive Rician fading CDMA channels , 1994, IEEE J. Sel. Areas Commun..