In this paper, we focus upon the effect of MUI on the channel estimation stage, through a non-parametric approach, in open-loop and closed-loop SpU-MIMO systems. The corresponding BER is integrated within a general framework for MAC-layer performance evaluation of ad-hoc networks. This framework is used to derive the throughput-related network performance and to provide corresponding numerical examples for ALOHA-based scenarios, along with analysis of various trade-offs.