High precision RF transmit power calibration based on recursive least squares estimation

Radio frequency (RF) transmit power calibration plays an important role in the design of wireless transceivers. In order to accurately control the level of the transmit power, this paper proposes a mathematical model for the the RF front-end module with closed-loop power control. By transforming transmit power calibration into a signal estimation problem, we are able to apply the recursive least squares (RLS) filtering algorithm to adaptively adjust the parameters of RF power amplifier so that the output power level can converge to the target rapidly. Compared with the traditional calibration method, the proposed calibration algorithm delivers better RF transmit power accuracy with lower computational complexity. The empirical results show that the proposed method is able to reduce the transmit power error from ±1.5 to ±0.25 dB.