Performance modeling of MIMO OFDM systems via channel analysis

Multiple-input multiple-output (MIMO) antennas can be combined with orthogonal frequency division multiplexing (OFDM) to achieve diversity gain and/or to increase system spectral efficiency through spatial multiplexing. In this letter, we derive the probability density function (pdf) expressions of the condition number (i.e., the maximum-to-minimum-singular-value ratio, MMSVR) of the channel state information (CSI) matrix. We show that this ratio is directly related to the noise enhancement in open-loop MIMO systems and provides a significant insight on the overall system capacity. The pdf of this ratio could be used to predict the relative performances of various MIMO configurations without complex system-level simulations. The pdf can also be used to compute the probability of whether certain channels fail in the high-throughput mode. Extensive simulations are performed to validate the accuracy of the closed-form pdf of the MMSVR derived in this letter