Adaptive digital techniques for efficiency and linearity enhancement of CMOS RF power amplifiers

This paper presents a baseband adaptive digital compensation technique for cost-effective CMOS integration of next-generation OFDM wireless transmitters. High power efficiency and linearity are simultaneously achieved by using a class-B power amplifier (PA) with less back-off and treating the memoryless AM-AM and AM-PM distortions in the digital domain. When a 64-QAM OFDM signal is transmitted, computer simulations indicate that the post-compensation ACPR and EVM are improved by 13 dB and 30 dB, respectively. The average power efficiency of the PA is 10.9% as opposed to 3.2% of a class-A counterpart for typical usage patterns.

[1]  T.H. Lee,et al.  Automatic phase alignment for a fully integrated CMOS Cartesian feedback power amplifier system , 2003, 2003 IEEE International Solid-State Circuits Conference, 2003. Digest of Technical Papers. ISSCC..

[2]  G. Kompa,et al.  Power amplifier modeling using memory polynomial with non-uniform delay taps , 2004, 34th European Microwave Conference, 2004..

[3]  Shu-Park Chan,et al.  A feedforward S-band MIC amplifier system , 1975 .

[4]  H. B. Wood,et al.  Linear amplification using envelope feedback , 1971 .

[5]  Youngoo Yang,et al.  A highly linear and efficient differential CMOS power amplifier with harmonic control , 2006, IEEE Journal of Solid-State Circuits.

[6]  C.-C. Hsieh.  A feedforward S-band MIC amplifier system , 1976, IEEE Journal of Solid-State Circuits.

[7]  Nick Pothecary,et al.  Feedforward Linear Power Amplifiers , 1999 .

[8]  Junxiong Deng,et al.  A SiGe PA with dual dynamic bias control and memoryless digital predistortion for WCDMA handset applications , 2005, IEEE Journal of Solid-State Circuits.

[9]  P.B. Kenington,et al.  A GSM-EDGE high power amplifier utilising digital linearisation , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).