Digital Predistortion for Power Amplifiers in Hybrid MIMO Systems with Antenna Subarrays

S, Lee; Kim, Minhyun; Sirl, Youngwook; Jeong, Eui-Rim; Hong, Soon-Il; Kim, Seongjin; Lee, Yong H.

doi:10.1109/vtcspring.2015.7145777

Cited by 54 publications

(46 citation statements)

References 11 publications

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“…The model can be fitted over several PA responses in least square (LS) sense, as in [4]. Two different LS estimation approaches are compared.…”

Section: Dpd Of Rf Beamforming Arraymentioning

confidence: 99%

“…T , and n denotes the time instant over N n time-domain samples [4]. Another approach proposed here is to minimise the array error in the desired direction (φ d , θ d ).…”

Section: Dpd Of Rf Beamforming Arraymentioning

confidence: 99%

“…In [2] and [3], the array DPD is adressed, but the experimental setup uses a reference antenna in the array far field, which might not be practical approach. Phased array DPD with common feedback is presented in [4] by modelling each PA independently. However, to the best of the author's knowledge, all the previously presented DPD approaches lack the effects of amplitude control and the concept of directed distortion presented in [5].…”

Section: Introductionmentioning

confidence: 99%

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Digital predistortion of amplitude varying phased array utilising over-the-air combining

Tervo

Aikio

Tuovinen

et al. 2017

2017 IEEE MTT-S International Microwave Symposium (IMS)

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Abstract-In this paper, we propose a simple polynomial linearisation technique for nonlinear phased arrays including amplitude control. Due to the large number of antennas and thus power amplifiers in the array, it is inefficient to linearise each power amplifier individually. Therefore, it is demonstrated that the array can be linearised over-the-air using single polynomial. The simulations show that the linearisation is achieved by first linearising the higher driven PAs at the precompression region and then cancelling the compression by the heavily expanding lower driven PAs. The proposed approach offers an alternative way of re-thinking the concept of array linearisation over multiple PAs.Index Terms-digital predistortion, hybrid beamforming, polynomial model, power amplifiers, 5G.

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“…The model can be fitted over several PA responses in least square (LS) sense, as in [4]. Two different LS estimation approaches are compared.…”

Section: Dpd Of Rf Beamforming Arraymentioning

confidence: 99%

“…T , and n denotes the time instant over N n time-domain samples [4]. Another approach proposed here is to minimise the array error in the desired direction (φ d , θ d ).…”

Section: Dpd Of Rf Beamforming Arraymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Digital predistortion of amplitude varying phased array utilising over-the-air combining

Tervo

Aikio

Tuovinen

et al. 2017

2017 IEEE MTT-S International Microwave Symposium (IMS)

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“…where |h e m | stands for the channel estimate, α e p,m , p = 1, 3, ..., P refer to the estimated coefficients of the direct model (13) has thus the same structure as the true received signal in (11). The observation signal is then utilized to generate the error signal considered for learning the DPD coefficients, expressed as…”

Section: B Combined Feedback Architecture and Dpd Learningmentioning

confidence: 99%

Digital Predistortion in Large-Array Digital Beamforming Transmitters

Brihuega

Anttila

Abdelaziz

et al. 2018

2018 52nd Asilomar Conference on Signals, Systems, and Computers

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In this article, we propose a novel digital predistortion (DPD) solution that allows to considerably reduce the complexity resulting from linearizing a set of power amplifiers (PAs) in single-user large-scale digital beamforming transmitters. In contrast to current state-of-the art solutions that assume a dedicated DPD per power amplifier, which is unfeasible in the context of large antenna arrays, the proposed solution only requires a single DPD in order to linearize an arbitrary number of power amplifiers. To this end, the proposed DPD predistorts the signal at the input of the digital precoder based on minimizing the nonlinear distortion of the combined signal at the intended receiver direction. This is a desirable feature, since the resulting emissions in other directions get partially diluted due to less coherent superposition. With this approach, only a single DPD is required, yielding great complexity and energy savings.Index Terms-5G, digital predistortion, power amplifiers, digital beamforming, large-array transmitters, out-of-band emissions, power amplifiers.

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“…Digital predistortion has been studied in the massive MIMO context in [11]- [14]. In [11], fully digital beamforming was assumed, and therefore a dedicated DPD unit for each transmitter is required.…”

Section: Introductionmentioning

confidence: 99%

Digital Predistortion for Hybrid MIMO Transmitters

Abdelaziz¹,

Anttila²,

Brihuega³

et al. 2018

IEEE J. Sel. Top. Signal Process.

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This article investigates digital predistortion (DPD) linearization of hybrid beamforming large-scale antenna transmitters. We propose a novel DPD processing and learning technique for an antenna sub-array, which utilizes a combined signal of the individual power amplifier (PA) outputs in conjunction with a decorrelation-based learning rule. In effect, the proposed approach results in minimizing the nonlinear distortions in the direction of the intended receiver. This feature is highly desirable, since emissions in other directions are naturally weak due to beamforming. The proposed parameter learning technique requires only a single observation receiver, and therefore supports simple hardware implementation. It is also shown to clearly outperform the current state-of-the-art technique which utilizes only a single PA for learning. Analysis of the feedback network amplitude and phase imbalances reveals that the technique is robust even to high levels of such imbalances. Finally, we also show that the array system out-of-band emissions are wellbehaving in all spatial directions, and essentially below those of the corresponding single-antenna transmitter, due to the combined effects of the DPD and beamforming.Index Terms-5G, digital predistortion, large-array transmitters, hybrid beamforming, power amplifiers, out-of-band emissions.

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Digital Predistortion for Power Amplifiers in Hybrid MIMO Systems with Antenna Subarrays

Cited by 54 publications

References 11 publications

Digital predistortion of amplitude varying phased array utilising over-the-air combining

Digital predistortion of amplitude varying phased array utilising over-the-air combining

Digital Predistortion in Large-Array Digital Beamforming Transmitters

Digital Predistortion for Hybrid MIMO Transmitters

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