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This article investigates the issue of low-cost digital predistortion (DPD) implementation in fixed-point field programmable gate array (FPGA) by considering the bitresolution along with lower number of coefficients. The impact of principle component analysis (PCA) on bit-resolution of DPD solution is proposed within the context of established DPD models. Unlike previously proposed PCA based solutions, it is established by simulation and measurement that the numerical stability problem associated with popular models such as memory polynomial (MP) can be alleviated when PCA is applied to the observation data matrix. It is reported with measurement results that PCA based model provides better linearization performance with the least memory size requirement and number of LUTs in 16-bit fixed-point FPGA operation than MP, orthogonal memory polynomial (OMP), and generalized memory polynomial (GMP) models. The performance of the proposed model, is evaluated in terms of normalized mean square error, adjacent channel error power ratio, matrix condition number, and dispersion coefficient for continuous Class-AB and ZX60-V631 power amplifiers using wide code-division multiple access signal (WCDMA) and long term evolution (LTE) signal with peak-to-average-power ratio (PAPR) around 9.895 and 11.92 dB, respectively. K E Y W O R D S behavioral modeling, digital predistortion (DPD), memory effect, memory polynomial (MP), order reduction, power amplifier (PA), principal component analysis (PCA) Int J RF Microw Comput Aided Eng. 2017;27:e21095.

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Carrier aggregation (CA) is an essential part of long-term evolution (LTE) signals for 4G/5G wireless communication. However, CA LTE signals place stringent conditions on the radio-frequency power amplifiers (PAs). The multi-band operation, wider bandwidth, and related hardware cost increase for the implementation of digital predistortion (DPD) for the multi-band PAs. This study presents a novel independent component analysis (ICA) method for the DPD models which is suitable for all three cases (intra-band contiguous, intra-band non-contiguous and inter-band non-contiguous) of CA. It has been established that the memory requirement of ICA-based memory polynomial (MP) model implementation is much lesser than the state-of-theart low complexity models such as MP model, orthogonal MP model and principal component analysis-based MP model for CA LTE signals. The proof-of-concept is provided with two different measurement setups for establishing its versatility.

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