Low-Complexity Subband Digital Predistortion for Spurious Emission Suppression in Noncontiguous Spectrum Access

Abstract

Noncontiguous transmission schemes combined withhigh power-efficiency requirements pose big challenges for radiotransmitter and power amplifier (PA) design and implementation.Due to the nonlinear nature of the PA, severe unwanted emissionscan occur, which can potentially interfere with neighboringchannel signals or even desensitize the own receiver in fre-quency division duplexing (FDD) transceivers. In this article, tosuppress such unwanted emissions, a low-complexity sub-band DPD solution, specifically tailored for spectrally noncontiguous transmission schemes in low-cost devices, is proposed. The proposed technique aims at mitigating only the selected spurious intermodulation distortion components at the PA output,hence allowing for substantially reduced processing complexity compared to classical linearization solutions. Furthermore, novel decorrelation based parameter learning solutions are also proposed and formulated, which offer reduced computing complexityin parameter estimation as well as the ability to track time-varying features adaptively. Comprehensive simulation and RF measurement results are provided, using a commercial LTE-Advanced mobile PA, to evaluate and validate the effectiveness of the proposed solution in real world scenarios. The obtainedresults demonstrate that highly efficient spurious components uppression can be obtained using the proposed solutions.

Publication
IEEE Transactions on Microwave Theory and Techniques
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