Fast Adjustment Scheme on Vector Regulator of Power Amplifier for Massive MIMO Base Stations

This paper proposes a fast adjustment scheme on vector regulator of power amplifier (PA) for Massive MIMO base stations. The configuration of the PA corresponds to a signal cancellation circuit of feed-forward PA. The proposed scheme estimates the input power to the PA using kNN (k-Nearest Neighbor) method based on the experimental data and sets the gain and phase values of the vector regulator in accordance with the estimated input power. Experimental results using 3.5 GHz-band PA show that the proposed scheme adjusts the vector regulator approximately within 15 seconds to achieve the target suppression amount of over 30 dB.