Signal-to-interference ratio estimation in CDMA systems

The paper is focused on estimating the signal-to-interference ratio (SIR) per multipath component in CDMA systems operating over frequency selective Rayleigh fading channels. A per-path SIR estimator is proposed and its performance is compared to the Cramer-Rao bound (CRB) derived for this problem. To account for the hardware limitations of portable mobile terminals, a low complexity version of the estimator is introduced and incorporated in the receiver structure. Based on the per-path SIR estimates, a new finger assignment algorithm (FAA) is proposed and compared to the conventional energy-based FAA. We show that the proposed FAA exhibits an improved multipath detection capability. Hence, more sophisticated multipath acquisition circuits can be realized based on the per-path SIR estimates.