  Multiple-input multiple-output (MIMO) techniques are becoming commonplace in
recent wireless communication standards. This added dimension (i.e., space) can
be efficiently used to mitigate the interference in the multi-user MIMO
context. In this paper, we focus on the uplink of a MIMO multiple access
channel (MAC) where perfect channel state information (CSI) is only available
at the destination. We provide a new set of sufficient conditions for a wide
range of space-time block codes (STBC)s to achieve full-diversity under
\emph{partial interference cancellation group decoding} (PICGD) with or without
successive interference cancellation (SIC) for completely blind users. Explicit
interference cancellation (IC) schemes for two and three users are then
provided and shown to satisfy the derived full-diversity criteria. Besides the
complexity reduction due to the fact that the proposed IC schemes enable
separate decoding of distinct users without sacrificing the diversity gain,
further reduction of the decoding complexity may be obtained. In fact, thanks
to the structure of the proposed schemes, the real and imaginary parts of each
user's symbols may be decoupled without any loss of performance. Finally, our
theoretical claims are corroborated by simulation results and the new IC scheme
for two-user MIMO MAC is shown to outperform the recently proposed two-user IC
scheme especially for high spectral efficiency while requiring significantly
less decoding complexity.
