In this paper, we study the performance of non-cooperative wireless multiple access systems with noisy separated channels, where correlated sources communicate to an access point (AP) in the presence of block-faded links. This is meaningful for pervasive wireless scenarios, e.g., wireless sensor networks, where information may be exchanged between a multitude of nodes. Our goal is to explore the potential benefits which can be obtained when source correlation is exploited at the AP, comparing the performance with that obtained by using distributed source coding (DSC) at the nodes. We consider both the average bit error probability and the outage probability as performance indicators, and we derive a theoretical approach to evaluate their li...