Throughput analysis of interference-limited MIMO-based cellular systems

Cell-wide mean throughputs on cellular system downlinks using multiple-input/multiple-output (MIMO) techniques is a topic of interest to researchers, cellular operators and equipment manufacturers. In previous work, the authors have tested the validity of the noise model (in the MIMO context) for the co-channel interference (CCI), wherein multipath-averaged CCI powers are added to the thermal noise power that results in an overall interference-plus-noise floor. This approximation simplifies throughput computation with only a minor loss of accuracy, while allowing the cell-wide mean throughput per user to be derived analytically. The key to the analysis is (i) the invocation of the noise model for CCI, and (ii) the demonstration that the overall CCI power has a distribution that is log-normal for any user distance from the base station (BS). This enables us to extend a previous analysis for single-cell (noise-only) MIMO systems to the interference-limited case.We present the analytical method and demonstrate its accuracy.