**7. Conclusion**

In this chapter, we studied the user selection based on the error probability of an actually employed MIMO detector in multiuser MIMO systems. As the complexity becomes prohibitively high if the user selection is based on exhaustive search (i.e., the combinatorial user selection), we considered a greedy user selection approach to keep the complexity low. We showed that low-complexity suboptimal detectors (i.e., the LR-based MMSE-SIC detector) with the MD criterion for the user selection can fully exploit both multiuser and receive diversity and provide good performance even though their complexity is low, which has been confirmed by both theoretical analysis and simulation results. Moreover, according to the simulation results, it was also shown that the LR-based detection with our proposed greedy user selection approach can achieve a similar diversity gain and have a comparable performance with that based on a combinatorial approach.
