Abstract:
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This paper addresses a model order reduction
technique based on Ridge’s regression for power amplifier (PA)
behavioral models to be used in digital predistortion (DPD)
linearization applications. Commonly, the DPD parameters’ extraction
is performed by means of a least squares (LS) regression.
With Ridge’s regression, the coefficients of the DPD are extracted
defining a weighted cost function aimed at minimizing not only
the mean square error, but also including a regularization term
based on the square of the Euclidean norm of the coefficients’
vector. Taking advantage of this regularization and following a
given criterium explained in this paper, it is possible to select
the most significant basis functions of the DPD model and thus,
not only improving the ovedetermined matrix problem, but also
reducing the model’s order and consequently the computational
complexity of the DPD linearizer. |