MIMO PA Linearization Pre-Processing for Full-Angle Beamforming
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Solution Overview
Problem
The non-linear distortion problem in multi-input multi-output (MIMO) systems, particularly in high-frequency broadband applications, affects spectral efficiency and communication quality, and existing digital pre-distortion (DPD) technologies struggle to optimize the performance of multiple power amplifiers due to differences in PA characteristics and frequency responses.
Innovation Solution
A MIMO PA full-angle linearization pre-processing method and device that utilizes alignment and pre-equalization filters, along with a DPD circuit unit, to unify the non-linear characteristics of multiple power amplifiers, ensuring linear consistency and performance across a full-angle range and high power, and addresses broadband response issues through pre-equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional DPD technology is used for single PA linearization, then linearization performance of single PA is improved, but it cannot simultaneously optimize performance of multiple PAs in MIMO system due to characteristics differences
Solution Approach 1:
The patent divides the MIMO system into multiple independent PA processing channels, each with its own DPD module. Each PA is processed separately through individual alignment filters and DPD circuits, allowing independent optimization of each PA's characteristics while maintaining overall system coherence through unified beamforming control.
Solution Approach 2:
The patent applies different DPD parameters and alignment filter coefficients to each PA based on its specific characteristics. Each PA receives customized pre-distortion parameters tailored to its individual non-linear characteristics, frequency response, and beamforming requirements, rather than using a uniform approach for all PAs.
2Manufacturing precision
If traditional DPD technology is applied to broadband applications, then narrowband linearization is achieved, but response differences under different frequencies increase linearization difficulty
Solution Approach 1:
The patent implements frequency-dependent DPD parameters and alignment filter coefficients that adapt to different frequency bands. The system dynamically adjusts pre-distortion parameters based on the operating frequency, allowing optimal linearization performance across the entire broadband range rather than compromising for average performance.
Solution Approach 2:
The patent changes DPD parameters, alignment filter coefficients, and pre-equalization parameters based on frequency, power level, and beamforming direction. These parameters are continuously adjusted to maintain optimal linearization performance across varying operating conditions, including different frequency bands and power levels.
3Manufacturing precision
If multiple DPD circuit units are used for each PA in MIMO system, then linearization performance of each PA is optimized, but system complexity and cost increase significantly
Solution Approach 1:
The patent merges the DPD functionality into a unified beamforming control unit that processes multiple PA signals simultaneously. Instead of separate DPD circuits for each PA, the system uses a single integrated control unit that generates appropriate DPD parameters and control signals for all PAs, reducing hardware complexity while maintaining performance.
Solution Approach 2:
The patent creates a universal beamforming control unit that performs multiple functions: beamforming weight calculation, DPD parameter generation, alignment filter control, and pre-equalization. This single multi-functional unit replaces what would otherwise require multiple separate circuit units, reducing overall system complexity.
4Reliability
If beamforming characteristics require good linearity in different directions, then directional performance is improved, but higher requirements are imposed on traditional DPD technology
Solution Approach 1:
The patent applies pre-equalization and alignment filtering before the DPD stage to pre-correct frequency response differences and non-linear characteristics. This preliminary processing reduces the burden on the DPD circuit by pre-conditioning the signals, allowing the DPD to focus on the remaining non-linearities and maintain linearity across different beamforming directions.
Data Source
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AI summary
Disclosed is a multi-input multi-output power amplifier (PA1, PA2) full-angle linearization pre-processing method. A first original signal is input to acquire first signals from power amplifiers (PAs) (PA1, PA2). Initial non-linear characteristics of each PA (PA1, PA2) are acquired based on the first original signal and the first signals. Alignment operations corresponding to target PAs (PA1, PA2) other than a reference PA are executed based on the first signals and the reference PA to acquire alignment parameter sets corresponding to the target PAs (PA1, PA2). The alignment parameter sets are applied to alignment filters (502-50N). A linearization operation is executed to the reference PA through inputting the first original signal into a digital pre-distortion circuit unit (400) in order to acquire a reference DPD parameter set of the DPD circuit unit (400) corresponding to the reference PA. The reference DPD parameter set is applied to the DPD circuit unit (400).