Analysis and Calibration of Nonlinear Power Amplifiers in Wideband OFDM-Based LEO Satellite Communication System

Low earth orbit (LEO) satellite communication system is vital due to its global coverage and low latency. To meet higher data rates, orthogonal frequency division multiplexing (OFDM) technology is recommended for adoption. In this paper, we analyze the nonlinear behavior of high-power amplifier (HPA) at Ka and Q/V frequency bands in wideband OFDM-based satellite communication system. A real satellite PA testing platform is constructed. Experimental results reveal that in wideband OFDM-based systems with high peak-to-average power ratio (PAPR), the conventional power back-off (PBO) method is no longer effective, particularly in mitigating in-band imbalance. Furthermore, we propose a low-complexity digital predistortion (DPD) scheme for satellite communication system. Experimental results demonstrate the robust performance of the proposed DPD.