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Abstract. Pseudo-Noise (PN) code synchronization is investigated in this and an accompanied paper for multicanier direct-sequence code division multiple access (DS-CDMA) systems on multipath Rayleigh fading channels. In this part, a new analysis is developed to evaluate accurately the mean acquisition time performance of serial search multiple-dwell acquisition systems. The method is unique in that it can take the correlations due to fading into account, including the correlations among different dwells and camers. In addition, the effects of system parameters on the acquisition performance such as carrier and user numbers, fading correlations, dwell number and times, and thresholds can be easily evaluated, as compared to computer simulations, and, therefore, facilitating the design of the acquisition subsystem. Our analytical results are verified by computer simulations.

The non-coherent second-order digital delay locked loop with the presence of Doppler shift is analyzed. The analysis is unique in two folds. First, the effects of the loop A/D quantization on the loop performance are examined that were neglected previously. Second, MTLL(mean time to lose lock) and MSE (mean square error) are evaluated more accurately than previous methods. Numerical results show that: (1) the number of quantization levels signiflcantly alters the loop behaviors, including the lock-in range, transient responses, M T L L and MSE; and (2) the traditional analysis based on Gaussian approximation may result in a large error in performance evaluation when the A/D quantization is taken into account.

A c c u r a t e performance evaluation of direct-sequence (DS) pseudo-noise code acquisition on Rayleigh fading channels is investigated i n this paper. Due to the correlations between cell detections i n c u r r e d b y fading, the traditional direct and Howgraph approaches for performance evaluation of an acquisition s y s t e m are not applicable to a fading channel. In this paper, a n e w analysis is proposed for accurate evaluation of the acquisition performance on Rayleigh fading channels. The analysis can include various search strategies, correlators and test methods w i t h different performance measures: probabili t y mass function (PMF) and/or moments of acquisit i o n time. Analytical and computer simulation results s h o w that the n e w method predicts the acquisition p e r f o r m a n c e v e r y accurately.

Abstract.Pseudo-noise code tracking with diversity reception is investigated for multi-camer direct-sequence code division multiple access (DS-CDMA) systems on multipath Rayleigh fading channels. The traditional noncoherent digital delay locked loop (DDLL) is analyzed under the effects of multipath fading and multiple access interference. A new decision-directed tracking loop based on a differentially-detected phase detector is proposed and analyzed. The new tracking loop significantly outperforms the traditional DDLL. Computer simulations have been conducted to verify our analytical results.