This paper deals with practical multi-antenna multiuser OFDM systems. With the additional degrees of freedom of multiple antennas and multiple subcarriers, the performance might be enhanced, but the scheduling complexity might increase exponentially. Since the scheduling with realistic integer signal mappings is an NP-complete combinatorial problem, suboptimum solutions based on the scalar product are good candidates to yield a fast and realizable practical implementation. We propose afterwards a power reuse strategy to lowerthe computational complexity, and show that the amount of signaling can be reduced by forcing an equal mapping for all the users at the same subcarrier.