Comparison of robustness of MIMO schemes in the presence of interference

Multiuser interference (MUI) is a major problem in an orthogonal frequency division multiplexing (OFDM) multiple access system due the absence of unique spreading codes being assigned to different users for separation at the receiver. In our paper, we propose the use of spatial separation techniques to separate users at the receiver. The two proposed interference mitigation techniques, defined as interference cancellation (IC) and interference suppression (IS), can be employed to mitigate interference. However, depending on the scenario and restrictions imposed on either of these two techniques, this requires careful consideration especially in a multiple input multiple output (MIMO) system. Two particular MIMO schemes, V-BLAST and dual Alamouti space time block code (STBC), which are strong candidates for future wireless systems, are introduced. Their robustness in the presence of interference is compared and the selection of appropriate interference mitigation techniques is suggested. Results obtained from our simulator are shown to support this study.