Selective Channel Inversion Precoding for the Downlink of MIMO Wireless Systems

In this paper a novel channel inversion (CI) precoding scheme is introduced for the downlink of multiple input multiple output (MIMO) systems. The proposed technique outperforms conventional CI by exploiting some of the consequential inter- channel interference (ICI). It achieves this by applying partial channel inversion such that the constructive part of ICI is preserved and exploited while the destructive part is eliminated by means of CI precoding. By doing so, the effective signal to interference-plus-noise ratio (SINR) delivered to the mobile unit (MU) receivers is enhanced, without the need to invest in additional transmitted signal power at the MIMO base station (BS). The trade-off to this achievement is a minor increase in the complexity of the BS processing. The presented theoretical analysis and simulations show that due to the SINR enhancement, significant performance gains are offered by the proposed MIMO precoding technique compared to its conventional counterpart.