ACLR Improvement Method for RF Power Amplifiers in Wireless Communication Systems

An efficient and practical method to improve Adjacent Channel Leakage Ratio (ACLR) by reducing intermodulation products within the carrier band and adjacent frequencies for power amplifiers via predistortion is introduced. The method proposed is evaluated on a commercial power amplifier where memory polynomial method is used for its characterization. The closed form relations are obtained to calculate the predistortion coefficients needed to cancel the intermodulation. A reduction of the intermodulation tones is achieved and led to the desired reduction of adjacent leakage for the system and distortion within the carrier band. The method introduced here can be used for wireless communication systems to reduce distortion on adjacent channels for applications such as 5G and WiFi 6, and can be implemented at the digital baseband stage where the amplitude and phase change in a QAM scheme.