Title :
A new digital predistorter linearizer for wide band signals
Author :
Lozhkin, Alexander N. ; Nakamura, Michiharu
Author_Institution :
YRP Center, Fujitsu Labs. Ltd., Yokosuka, Japan
Abstract :
This paper presents a new method of digital adaptive predistortion for linearization of high-power amplifiers (HPAs) that mitigates linearization performance deterioration due to bandwidth limitation of feedback path. With increases of signal bandwidth, the effects of limited bandwidth of the predistorter feedback path cannot be ignored. In the proposed algorithm, adaptation is derived from direct learning for the lookup table (LUT) gains. According to the proposed approach, when the LUT contents are adapted according to an LMS algorithm, several other LUT entries adjacent to the currently processed entry are also updated. However, the level of adaption for adjacent entries is less than for the currently processed entry. This level is defined by the preselected window weight function. The proposed algorithm makes it possible to design a low-complexity, memoryless adaptive predistortion system with narrowband feedback path to compensate for the nonlinearity of an HPA.
Keywords :
circuit complexity; digital communication; feedback amplifiers; least mean squares methods; linearisation techniques; memoryless systems; signal processing; HPA nonlinearity; LMS algorithm; LUT gains; digital adaptive predistortion; digital predistorter linearizer; feedback path bandwidth limitation; high-power amplifier linearization; linearization performance deterioration; lookup table; low-complexity memoryless adaptive predistortion system design; narrowband feedback path; predistorter feedback path; signal bandwidth; wide band signals; Bandwidth; Baseband; Distortion; Mathematical model; OFDM; Predistortion; Table lookup; DPD; HPA; baseband predistortion; linearization; memory effect; power amplifier;
Conference_Titel :
Personal Indoor and Mobile Radio Communications (PIMRC), 2011 IEEE 22nd International Symposium on
Conference_Location :
Toronto, ON
Print_ISBN :
978-1-4577-1346-0
Electronic_ISBN :
pending
DOI :
10.1109/PIMRC.2011.6139727