Behavioral Modeling of RF Power Amplifiers with Carrier-Frequency Generalization Using Interpolated Memory Polynomials

Power amplifier behavioral modeling is an important technique for efficient and accurate digital predistortion, but conventional models fail to generalize when applied across varying carrier frequencies. This work addresses the carrier-frequency generalization by proposing a parameterized memory polynomial (PMP) modeling approach. The method involves extracting memory polynomial models at multiple carrier frequencies and interpolating their coefficients using spline interpolation, resulting in a single model capable of operating across a wide carrier-frequency band. Experimental validation was conducted using measured input–output PA responses over the 3.3–3.8 GHz range. Results obtained show that PMP built on three carrier frequencies achieves up to 9 dB average NMSE improvement compared to the fixed-coefficient MP model. The proposed model nearly matches the accuracy of the MP model at the entire measured range. The overall accuracy depends on the combination of the introduced interpolation error and the discrepancy between the initial MP model fitting errors. The proposed method offers a practical solution for PA modeling in systems requiring fast frequency agility, such as carrier aggregation and dynamic spectrum access, eliminating the need for model retraining at each operating frequency.