Multiplexing efficiency for MIMO antenna-channel impairment characterisation in realistic multipath environments

Multiple-input multiple-output (MIMO) systems in multipath environments suffer from high correlations (in the presence of small angular spreads of propagation waves and similar antenna patterns) and power imbalances [(due to cross-polarisation discrimination (XPD) of the propagation channel and possibly different antenna efficiencies)]. A simple performance metric that takes into account of the antenna-channel impairments on the MIMO system will be of great value for MIMO antenna characterizations. In this work, a generalized multiplexing efficiency (ME) is derived, which takesing into account of antenna pattern and polarisation mismatches in arbitrary multipath environments. In addition, it is shown that the generalised SM efficiencyME can characterise not only the throughput (or coded error rate) degradation but also the degradation of uncoded error rate. For verifying the generalised SM efficiencyME, we use both the correlation-based channel model (where correlations and power imbalances can be readily specified) and the more realistic WINNER+ channel model (where correlations and power imbalances have to be indirectly controlled by changing the antenna setup).