Full-Angle Digital Predistortion of 5G Millimeter-Wave Massive MIMO Transmitters

Yu, Chao; Jing, Jianxin; Shao, Han; Jiang, Zhi Hao; Yan, Pinpin; Zhu, Xiao‐Wei; Wang, Hong; Zhu, Anding

doi:10.1109/tmtt.2019.2918450

Cited by 81 publications

(62 citation statements)

References 28 publications

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“…Furthermore, the lower losses of its SiC substrate help to reduce crosstalk in a multi-channel PA, which has been shown to have the most detrimental effect on the performance of MIMO systems [5]. Although some crosstalk cancellation techniques have been developed for MIMO transmitters using digital a predistortion (DPD), e.g., [9], it is still essential to achieve high linearity and low crosstalk at the raw circuit-level implementation.…”

Section: Introductionmentioning

confidence: 99%

A Fully Integrated GaN Dual-Channel Power Amplifier With Crosstalk Suppression for 5G Massive MIMO Transmitters

Nikandish

Staszewski

Zhu

2021

IEEE Trans. Circuits Syst. II

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We present a broadband dual-channel power amplifier (PA) with crosstalk suppression for multi-input multioutput (MIMO) communications. Operation of MIMO system with crosstalk is theoretically evaluated for two popular coding schemes including the space-time coding and linear precoding. Design challenges of a multi-channel PA on a single chip are investigated and circuit techniques, including second-harmonic trapping integrated into the output matching network and the use of back-via lines to isolate the channels, are proposed to mitigate the inter-channel crosstalk. A fully integrated dualchannel PA prototype, implemented using a 250-nm GaN-on-SiC process, provides 34.9-36.3 dBm output power, 44-49% poweradded efficiency (PAE), 11.3-12.3 dB power gain, 31.0-34.2 dB second-harmonic rejection, and −28.1 dB to −25.7 dB interchannel crosstalk across 4.5-6.5 GHz. For a 100-MHz 256-QAM signal with 7.2 dB peak-to-average power ratio (PAPR), the PA achieves 29.9 dBm average output power, 30% average PAE, −38.2/−39.1 dBc adjacent channel leakage ratio (ACLR), and −28.2 dB (3.9%) rms error vector magnitude (EVM), without using digital predistortion (DPD). Effect of crosstalk on linearity of the dual-channel PA is also measured and it is shown that for a 256-QAM signal EVM can increase by 3-8 dB, depending on relative power levels of the two channels.

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Section: Introductionmentioning

confidence: 99%

A Fully Integrated GaN Dual-Channel Power Amplifier With Crosstalk Suppression for 5G Massive MIMO Transmitters

Nikandish

Staszewski

Zhu

2021

IEEE Trans. Circuits Syst. II

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“…The uniformity of PAs is crucial in group DPD. Recently, [9] proposed tuning boxes for each PA, but this structure still needs at least one digital tuning component for each PA. The other way to solve this problem is to optimize the linearity of the primary beam signal, which means bad linearity in each channel but excellent linearity in the primary direction beam after signal combination in space [10]- [14].…”

Section: Introductionmentioning

confidence: 99%

Analog Predistorter Averaged Digital Predistortion for Power Amplifiers in Hybrid Beam-Forming Multi-Input Multi-Output Transmitter

You

et al. 2020

IEEE Access

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For higher data throughput, the Massive Multi-input Multi-output (MIMO) system has been widely used in modern communication systems. Due to the circuit size and power consumption, it is difficult to integrate one Radio Frequency (RF) chain for each power amplifier (PA). As a result, MIMO transmitters with hybrid beam-forming don't have enough RF chains, and this demands the digital predistortion (DPD) block to deal with several power amplifiers (PA) simultaneously, which causes a shared DPD problem. This paper presents an Analog Predistorter Averaged DPD (A 2-DPD) for hybrid beam-forming massive MIMO transmitters. To linearize more than one PAs with one shared digital predistortion unit, continuously tunable Analog Predistortion (APD) modules are employed to uniform the nonlinear behavior of PAs in each channel. Based on iterative learning control (ILC) technique, crossed normalized mean square error (CNMSE) is derived to judge the uniformity of PAs. By comparing the CNMSE of each PAs, the best similarity state of PAs can be found. The nonlinear behavior of PAs can be adjusted to a similar state by tuning the APD control voltage. The adjustment makes PAs easier to be linearized by a shared DPD. Furthermore, an averaged DPD algorithm is proposed to improve the total linearity performance for each PA. Simulations are performed to study the relationship between CNMSE and PA uniformity and further simulations show the ability of A 2-DPD to deal with a multi-PA scenario. In the end, to verify the feasibility of the proposed A 2-DPD, two class-AB PAs with operating frequency at 3.5 GHz with the same type transistor and similar design are tested. Experimental results show the proposed A 2-DPD can significantly improve the uniformity of PAs and the Adjacent Channel Power Ratio (ACPR) can be improved by 8 dB compared with using the DPD parameter of the other PA.

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“…In multi‐branch and multi‐band transmitters, predistortion is one of the most prominent techniques for linearisation of non‐linearities and digital predistortion (DPD) technique employs the existing digital signal processor of the base station's transmitter using the concept of software‐defined‐radios [6–30]. The power consumption in implementing DPD on the digital signal processor is relatively low as compared to the high power consumption of PA.…”

Section: Introductionmentioning

confidence: 99%

“…In [27], a neural‐network‐based DPD model is presented for compensation of PA non‐linearity, IQ imbalance, dc offset and crosstalk in MIMO transmitter. In [28–30], DPD models are proposed for mitigation of PA non‐linearities in hybrid massive MIMO transmitters. However, these DPD models [28–30] do not account for non‐linear crosstalk.…”

Section: Introductionmentioning

confidence: 99%

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Efficient linearisation technique for crosstalk and power amplifier non‐linearity suitable for massive MIMO transmitters

2020

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Full-Angle Digital Predistortion of 5G Millimeter-Wave Massive MIMO Transmitters

Cited by 81 publications

References 28 publications

A Fully Integrated GaN Dual-Channel Power Amplifier With Crosstalk Suppression for 5G Massive MIMO Transmitters

A Fully Integrated GaN Dual-Channel Power Amplifier With Crosstalk Suppression for 5G Massive MIMO Transmitters

Analog Predistorter Averaged Digital Predistortion for Power Amplifiers in Hybrid Beam-Forming Multi-Input Multi-Output Transmitter

Efficient linearisation technique for crosstalk and power amplifier non‐linearity suitable for massive MIMO transmitters

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