TY - JOUR
T1 - Code-Timing Estimation for Long-Code CDMA Systems with Bandlimited Chip Waveforms
AU - Wang, Rensheng
AU - Li, Hongbin
PY - 2003
Y1 - 2003
N2 - In this paper, we present a code-timing estimation scheme for asynchronous direct-sequence (DS) code-division multiple-access (CDMA) systems with aperiodic (long) spreading codes and bandlimited chip waveforms. The proposed scheme first converts the observed signal to the frequency domain by fast Fourier transform (FFT). Then, a nonlinear least-squares (NLS) criterion is invoked to fit the unknown parameters to the frequency-domain data. While the exact minimizer of the NLS criterion requires computationally prohibitive searches over a multi-dimensional parameter space, we propose an efficient approach that iteratively estimates one user/path at a time via simple linear processing and, furthermore, combines successive interference suppression (SIC) with parameter re-estimation for improved code acquisition performance. Simulation results show that the proposed scheme achieves a significantly larger user capacity and faster acquisition time than the SIC and a standard matched-filter based code acquisition techniques in time-varying fading channels.
AB - In this paper, we present a code-timing estimation scheme for asynchronous direct-sequence (DS) code-division multiple-access (CDMA) systems with aperiodic (long) spreading codes and bandlimited chip waveforms. The proposed scheme first converts the observed signal to the frequency domain by fast Fourier transform (FFT). Then, a nonlinear least-squares (NLS) criterion is invoked to fit the unknown parameters to the frequency-domain data. While the exact minimizer of the NLS criterion requires computationally prohibitive searches over a multi-dimensional parameter space, we propose an efficient approach that iteratively estimates one user/path at a time via simple linear processing and, furthermore, combines successive interference suppression (SIC) with parameter re-estimation for improved code acquisition performance. Simulation results show that the proposed scheme achieves a significantly larger user capacity and faster acquisition time than the SIC and a standard matched-filter based code acquisition techniques in time-varying fading channels.
UR - http://www.scopus.com/inward/record.url?scp=0141563729&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0141563729&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:0141563729
SN - 1520-6149
VL - 4
SP - 109
EP - 112
JO - ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings
JF - ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings
T2 - 2003 IEEE International Conference on Accoustics, Speech, and Signal Processing
Y2 - 6 April 2003 through 10 April 2003
ER -