Performance Analysis of Multiple Antenna Multi-User Detection

We derive the diversity order of some multiple antenna multi-user cancellation and detection schemes. The common property of these detection methods is the usage of Alamouti and quasi-orthogonal space-time block codes. For detecting $J$ users each having $N$ transmit antennas, these schemes require only $J$ antennas at the receiver. Our analysis shows that when having $M$ receive antennas, the array-processing schemes provide the diversity order of $N(M-J+1)$. In addition, our results prove that regardless of the number of users or receive antennas, when using maximum-likelihood decoding we get the full transmit and receive diversities, i.e. $NM$, similar to the no-interference scenario.