Hardware-efficient compensator for outphasing power amplifiers
AssigneeMassachusette Institute of Technology
InventorsYan Li, Zhipeng Li, Alexandre Megretski, Vladimir Marko Stojanovic, Omer Tanovic, Yehuda Avniel
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Abstract
Digital compensators for use in outphasing-based power amplification systems (e.g., Linear Amplification using Nonlinear Components (LINC) amplifiers and Asymmetric Multilevel Outphasing (AMO) amplifiers) include a short memory nonlinear portion and a long memory linear time invariant (LTI) portion. In various embodiments, compensators are provided that are of relatively low complexity and that are capable of operation at throughputs exceeding a Gigasample per second.
Claims28
An outphasing power amplification system comprising:
- an input to receive a data sequence;
- a shaping filter to shape pulses within the data sequence to control a spectrum thereof;
- a signal component separator (SCS) to separate the shaped data sequence into first and second signal components, the first signal component including at least a first phase signal and the second signal component including at least a second phase signal;
- first and second power amplifiers to amplify the first and second signal components, respectively;
- a combiner to combine output signals of the first and second power amplifiers to generate an output signal of the outphasing power amplification system;
- a compensator circuit coupled between the SCS and the first and second power amplifiers to adjust phases in the first phase signal and the second phase signal in a manner that linearizes operation of the outphasing power amplification system;
- and
- a phase modulator coupled between the compensator and the first and second power amplifiers to modulate carrier signals using the compensated first and second phase signals, wherein the phase modulator is coupled to deliver the modulated carrier signals to respective ones of the first and second power amplifiers;
- wherein the compensator circuit includes a first stage and a second stage, the first stage to provide non-linear transformations to the first and second signal components generated by the SCS and the second stage to provide linear time invariant (LTI) transformations to the output signals of the first stage, the LTI transformations having discontinuities at ±π, wherein the second stage outputs the compensated first and second phase signals to the phase modulator.
A compensation circuit for improving linearity in outphasing power amplification systems, the compensation circuit to be placed between a signal component separator (SCS) and first and second power amplifiers of an outphasing power amplification system to adjust phases of first and second phase signals to be input to the first and second power amplifiers, the compensation circuit comprising:
- a first stage coupled to receive first and second signal components output by the SCS, the first stage including first circuitry to provide a first non-linear transformation to the first signal component and second circuitry to provide a second non-linear transformation to the second signal component, the first signal component including at least a first phase signal and the second signal component including at least a second phase signal;
- and
- a second stage coupled to receive output signals of the first stage, the second stage including third circuitry to apply linear time invariant (LTI) transformations to the output signals of the first stage to generate corrected phase signals for the first and second power amplifiers, the LTI transformations having discontinuities at ±π, wherein the third circuitry includes at least one complex-valued finite impulse response (FIR) filter to process signals received from the first circuitry of the first stage and at least one complex valued FIR filter to process signals received from the second circuitry of the first stage;
- wherein the first stage has relatively short memory and the second stage has relatively long memory.
Dependencies are inferred from the claim text.