Predistorter for MIMO System With Nonlinear Power Amplifiers

A multiple input multiple output (MIMO) system with nonlinear power amplifiers (PAs) is considered. The nonlinear PAs distort the transmitted signal causing performance degradation. The common approach for the mitigation of nonlinear distortions is the linearization of each one of the PAs in the MIMO system separately. We propose to apply a more generic approach in the form of a global linearization of the entire
nonlinear MIMO channel
. The aim of the global linearization is to reduce the nonlinear distortions seen at the receiver. An iterative technique is proposed for the implementation of such a linearization. The proposed technique improves the system performance, including: 1) power efficiency of the PAs, 2) quality of the received signal, measured in terms of symbol error rate, and 3) spectral purity of the transmitted signals.