Digital predistortion has been proposed to linearize the power amplifier (PA) for nonconstant envelope modulation schemes. In this paper, we propose an enhanced memory polynomial model for wideband digital predistortion of nonlinear power amplifiers. By including the cross-combination memory terms of
Volterra model, the proposed model is much less complex while maintains excellent linearity performance as compared to the conventional memory polynomial and generalized memory polynomial model. The adaptive parameter estimation of the predistortion system is realized using a householder block exact QR-decompositionbased recursive least squares (QRD-RLS) algorithm. Performance of the householder block exact inverse QRDRLS
algorithm is studied via computer simulations. Measurements are carried out for a highly nonlinear class-AB PA. The captured IQ baseband signal of the PA is used for behavioral model generation and predistorter performance validation. The results show that correction of an adjacent channel power ratio (ACPR) up to 25 dB is achieved at 5 MHz frequency offset for a WCDMA input having 5 MHz instantaneous bandwidth.
LI Ming-yu, LIU Jin-ting, FENG Wen-jiang, JIANG Yang
. Householder Block Exact Inverse QR-Decomposition Recursive Least Squares Method in Adaptive Digital Predistortion System[J]. Journal of Applied Sciences, 2013
, 31(4)
: 345
-352
.
DOI: 10.3969/j.issn.0255-8297.2013.04.003
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