Blind estimation of FIR channels in CDMA systems with aperiodic spreading sequences
Murat Torlak, Brian L. Evans, Guanghan Xu · 2002
CDMA systems commonly use aperiodic spreading codes to distribute a signal spectrum uniformly over the channel bandwidth and differentiate neighboring cell sites. CDMA receivers often suffer from interference due to multipath fading. Blind signal estimation schemes cannot be used because they require periodic spreading sequences. RAKE receivers are often used, but they cannot fully exploit the rich structure of CDMA signals to minimize interference. This paper presents an iterative technique to estimate multipath parameters which can serve as a preprocessing step in a receiver to increase signal-to-interference ratio. We investigate the performance of the proposed method using computer simulations. Preliminary simulation results show an average of 10 dB gain on channel parameter estimation.