In this paper, we propose an iterative SIC receiver architecture with pilot- and data-based channel estimation for efficient decoding of non-orthogonal superimposed signals. The non-orthogonal superposition concept on top of OFDMA is a promising technique to improve cell spectral efficiency. In the cellular case, where users with significant path loss are superimposed by an intelligent scheduler, the SIC multi-user receiver scheme is well adapted for user signal separation. Based on the proposed receiver, we show the performance by means of multi-link link-level simulations in a realistic OFDMA uplink system including channel estimation based on real pilot patterns. Keywords- Non-orthogonal superposition; iterative SIC receiver; multi-user; iterative channel estimation; MMSE; OFDMA;