Cross-Layer Criterion for MIMO Spatial Multiplexing Systems with Imperfect CSI

In this paper, we investigate a cross-layer transmit antenna selection (T-AS) approach for multiple-input multiple-output spatial multiplexing (MIMO-SM) systems, that employ decision-feedback detector (DFD), over Ricean flat-fading channels. The selected transmit antennas are those that maximize the link layer throughput of MIMO channels. A closed-form expression for the system throughput with imperfect channel state information (CSI) is derived. Extensive simulation results are provided for the system performance assessment, showing that the cross-layer T-AS scheme always assigns the transmission to the antenna combination which sees better channel conditions, resulting in a substantial improvement over the optimal capacity- based T-AS approach. Our results show that the capacity-based T-AS is more robust to imperfect channel estimation. However, in all cases, the cross-layer T-AS delivers higher throughput gains than the capacity-based T-AS.