Eigenvector Informed Precoder Design for Active MIMO Transmitters

Integrated active arrays prefer to eliminate isolators for compact, low-cost, and power-efficient transmitter designs to support growing throughput demands in future mobile networks. However, the integrated active array suffers from loadpulling effects due to antenna mutual coupling, causing PA nonlinearity and signal distortion. This paper proposes an eigenvector informed precoder design based on the eigen-decomposition of the antenna array Scattering-matrix (S-matrix), which reduces the variation of active reflection coefficient (ARC) and, thus, mitigates the loadpulling effect. Simulation results for a 16 × 4 multiple input and multiple output (MIMO) system validate the effectiveness of the proposed method, showing a more localized PA ARC distribution in the Smith chart when compared to that with the conventional zero-forcing (ZF) precoding.