Description
A new formulation is used for the Radio Frequency (RF) Power Amplifier (PA) surface model and predistorter model along with the sparse regression techniques that are 500x faster for the bandwidth limited envelope tracking power amplifiers (ETPA) and that reduce the number of model coefficients 12x (600 to 50) to improve the linearity and the power efficiency of the RF PA for high Peak to Average Power Ratio (PAPR) signals resulting due to the carrier aggregation (CA). Slew rate limited power supply techniques are used to reduce the bandwidth of the supply modulator waveform because the supply modulators do not have the bandwidth to deal with most carrier aggregated waveforms. A Slew rate limited ETPA is used in conjunction with the 2-D digital predistortion (DPD) to improve the power efficiency and the linearity of the RF PA. Doubly Orthogonal Matching Pursuit algorithm (DOMP) is used with DPD to achieve 12x model-order reduction and Reduced Complexity-DOMP to speed up the parameter estimation. The two test signals that are used to demonstrate this technique are four carrier aggregated waveforms at 3.7 GHz , with 37dBm output power, < 3.5% EVM, and < -37dBc ACLR after DPD.
