Digital Predistortion for Hybrid MIMO Transmitters

Abstract

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 well-behaving in all spatial directions, and essentially below those of the corresponding single-antenna transmitter, due to the combined effects of the DPD and beamforming.

arXiv commentAccepted for publication in IEEE Journal of Selected Topics in Signal Processing

References in corpus (3)

• Massive MIMO for Next Generation Wireless Systems
• Massive MIMO Systems with Non-Ideal Hardware: Energy Efficiency, Estimation, and Capacity Limits
• Out-of-Band Radiation Measure for MIMO Arrays with Beamformed Transmission

Cited by in corpus (7)

• Performance, Power, and Area Design Trade-offs in Millimeter-Wave Transmitter Beamforming Architectures
• Piecewise Digital Predistortion fo mmWave Active Antenna Arrays: Algorithms and Measurements
• Digital Predistortion for Multiuser Hybrid MIMO at mmWaves
• On Antenna Array Out-of-Band Emissions
• Linearizing Active Antenna Arrays: Method and Measurements
• A Comprehensive Performance Analysis for mm-Wave Massive MIMO Hybrid Beamforming under PA Nonlinearities
• Digital Predistortion in Large-Array Digital Beamforming Transmitters