Title :
Adaptive channel estimation algorithm for QS-CDMA signals
Author_Institution :
Nokia Res. Center, Irving, TX, USA
Abstract :
In this paper, we consider an adaptive channel estimator for quasi-synchronous CDMA (QS-CDMA) systems, where mobiles synchronize their transmission to a common GPS-generated clock. An extended Kalman filter (EKF) is employed to track user delays and channel coefficients. QR decomposition with the M-algorithm (QRD-M) is proposed for data detection. However, due to the EKF, the computational complexity is still high. To minimize this computational complexity, we employ an adaptive channel estimator for QS-CDMA signals, where the EKF is adaptively applied depending on the quasistationarity of the channel in two symbol intervals.
Keywords :
Kalman filters; adaptive estimation; adaptive signal detection; code division multiple access; computational complexity; mobile radio; multiuser channels; spread spectrum communication; EKF; GPS-generated clock; M-algorithm; QR decomposition; QRD-M; QS-CDMA signals; adaptive channel estimation algorithm; channel coefficient tracking; channel quasi-stationarity; computational complexity; data detection; extended Kalman filter; mobile radio; quasi-synchronous CDMA systems; symbol intervals; transmission synchronization; user delay tracking; Bit error rate; Channel estimation; Computational complexity; Delay; Multiaccess communication; Multiuser detection; Spread spectrum communication; Statistical analysis; Statistical distributions; Testing;
Conference_Titel :
Signals, Systems and Computers, 2001. Conference Record of the Thirty-Fifth Asilomar Conference on
Conference_Location :
Pacific Grove, CA, USA
Print_ISBN :
0-7803-7147-X
DOI :
10.1109/ACSSC.2001.987742
