Digital predistortion technique for low resource consumption using carrier aggregated 4G/5G signals

Abstract

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.

Beyond the Moore-Penrose Inverse: Strategies for the Estimation of Digital Predistortion Linearization Parameters

“…This scenario is similar to intermodulation distortions (IMD) and cross-modulation distortions generated by the PA while driven by multi-carrier and carrier aggregation modulated signals. According to the results provided in [36], thanks to the proposed pruning method based on ICA, the required memory resources for implementing the DPD linearizer are significantly reduced.…”

An Efficient VLSI Architecture for FastICA by Using the Algebraic Jacobi Method for EVD

“…A System-on-Chip (SoC) based implementation of FastICA for dynamic background subtraction in real-time and portable vision devices is deployed in [17]. A field-programmable gate array (FPGA) based implementation of ICA is adopted in [18] for digital pre-distortion (DPD) in wireless communication systems. Moving average ICA for real-time applications is evaluated in [19].…”

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

“…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.…”

“…Many DPD models such as volterra‐series [6], memory polynomial (MP) [7], adapted MP with two‐dimensional (2D) indexing [8], complex gain convergence [9], lookup table‐based adaptive DPD [10] and steepest descent approach‐based direct learning DPD [11] have been proposed for linearisation of PA in single‐input–single‐output (SISO) transmitter. Many predistortion techniques have been proposed for multi‐carrier, multi‐band transmitters and satellite channels [12–17].…”