User recognition and signature code acquisition for CDMA receivers

Fast and reliable signal sense and signature code synchronization for direct-sequence spread spectrum (DS-SS) signals are key issues in the design of the receiver for modern packet code-division multiple access (CDMA) radio networks. This is the motivation for the study of the signal recognition and code acquisition (SR/CA) scheme described. Specifically, starting form elementary estimation theory criteria, we work out a non-coherent parallel SR/CA algorithm that is easily suited to a low-complexity full-digital implementation, possibly in a single application-specific integrated circuit (ASIC). The results of a theoretical analysis of such a scheme, encompassing additive white Gaussian noise (AWGN) and multiple access interference (MAI), are integrated and validated by an overall time-domain system simulation. We also evaluate through a simplified approach the impact of some degradation factors on the overall circuit performance, namely the sampling epoch and carrier frequency offset, and one-bit signal quantization, to allow the optimization of the design parameters as a function of the characteristics of the received signal