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This article presents a scalable digital predistortion (DPD) linearizer for handset power amplifiers (PAs) with nonflat frequency response and assuming a 5G scenario with dynamic resource blocks (RBs) reallocation. The scalable DPD model is designed to be both bandwidth and frequency-dependent, including some design constraints targeting a resource-efficient hardware implementation. In order to extract the most relevant basis functions that better trade-off the linearization performance and the required resources of a hardware implementation of the DPD, a feature selection technique based on a constrained version of the doubly orthogonal matching pursuit (DOMP) is proposed. The linearization performance of the proposed DPD method is evaluated on a PA system-on-chip (SoC), considering 5G new radio (NR) signals at different frequency locations and with different bandwidths within a 100 MHz channel.

This paper presents two linearization strategies for a custom-designed wideband push-pull (PP) power amplifier (PA) for wired communication applications such as, for example, cable TV. Two digital predistortion (DPD) behavioral models are proposed to meet the in-band and out-of-band linearity requirements when efficiently amplifying wideband DOCSIS signals with high fractional bandwidth (FBW). A radiofrequency (RF) DPD linearizer based on a band-pass generalized memory polynomial (BP-GMP) behavioral model and a baseband (BB) I-Q DPD linearizer based on a harmonic distortion GMP (HD-GMP) behavioral model are proposed. Both DPD models take into account the harmonic distortion typical of high FBW amplification. Experimental results will show high efficient and linear amplification of a $4\times192$ MHz composite DOCSIS signal by properly combining a crest factor reduction (CFR) technique and the proposed DPD strategies.

This article presents a low-complexity linearization method to compensate for multisource nonlinear distortion in wideband envelope tracking (ET) power amplifiers (PAs) for 5G new radio (NR) mobile terminals. The proposed linearization approach consists in an envelope leakage cancellation (ELC) system operating in the dynamic supply path and a 2-D digital predistortion (2-D-DPD) linearizer acting on the baseband complex modulated signal. In a first step, an envelope generalized memory polynomial (EGMP) behavioral model is proposed to compensate for the unwanted radio frequency (RF) leakage that appears at the output of ET modulator (ETM). Then, a baseband 2-D-DPD linearizer based on a slow envelope-dependent generalized memory polynomial (SED-GMP) behavioral model is used to further enhance the linearization performance. The proposed method is validated on a system-on-chip (SoC) ET PA board for mobile applications. The reported experimental results show how the proposed digital linearization approach can mitigate the linearity and efficiency trade-off in ET PAs. Consequently, the out-of-band linearity requirement of −36 dBc of adjacent channel power ratio (ACPR) is met for 5G-NR test signals with bandwidths ranging from 60 to 200 MHz at 2.55 GHz (band B41), with an overall ET PA power efficiency ranging from 10.1% and up to 16.5%, depending on the signal bandwidth.

This paper focuses on the interplay between data throughput and battery duration in UWB units, both of which the most perceptible at the user' level. The potential benefits of enlarging the power amplifier back-off (linearity) are assessed for different channel conditions according to a communication system following the IEEE 802.15. 3a standard (MB-OFDM proposal). New performance results are presented which highlight the kinds of channels where an increase in transmit linearity (power amplifier back-off enlargement) yields increased data throughput, and those where it does not. Results show whether designs sacrificing power efficiency have a benefit in data rate increase or it is simply a power spoil (ineffective reduction of battery's time-of-life). Index Terms--UWB, MB-OFDM, Power amplifiers, multipath, Back-off.