Statistical Transmit Antenna Subset Selection for Limited Feedback MIMO Systems

In this paper, we investigate statistical transmit antenna subset selection to improve the capacity of wireless multiple-input multiple-output (MIMO) systems with linear receivers. In order to reduce feedback overhead, we allocate equal power and equal rate to all selected transmit antennas. The equal data rate is determined by the minimum post-detection signal-to-noise ratio (SNR) and adjusted every channel instance. To reduce feedback overhead further and channel estimation burden for all transmit antennas every channel instance, the antenna selection is based on the long-term statistics of spatially correlated MIMO fading channels. In particular, we first derive an analytical closed-form expression for the expectation of the lower bound on the capacity using the smallest eigenvalue distribution of a Wishart matrix. Then, we propose a transmit antenna subset selection criterion of maximizing this average lower-bound capacity. Numerical results show that the proposed selection scheme improves the performance with small feedback overhead