Multi-Band DPD Lookup Table Updating With Phase-Calibrated Coefficients

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Solution Overview

Problem

Current methods for updating pre-distortion coefficient lookup tables in multi-frequency band communication systems are inefficient due to high calculation complexity and instability of pre-distortion coefficients, particularly when processing signals from multiple frequency bands.

Innovation Solution

A method and system that collect and process reference and feedback signals from multiple frequency bands to calculate and phase-calibrate pre-distortion coefficients, updating lookup tables accordingly, while introducing a constant weighting coefficient to simplify calculations and improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If single frequency band processing method is used for multi-frequency band signals, then the processing can be implemented, but the calculation complexity becomes high and the pre-distortion coefficients become unstable

Engineering Contradiction:
Improvestability of pre-distortion coefficientsVSAvoidcalculation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the multi-frequency band signal processing into separate frequency band processing units. Each frequency band has its own lookup table and pre-distortion coefficient set, allowing independent processing. This segmentation reduces the overall calculation complexity by avoiding joint processing of all frequency bands simultaneously, while improving coefficient stability through frequency-selective optimization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different pre-distortion coefficients to different frequency bands based on their specific characteristics. Each frequency band's lookup table is optimized locally for that band's signal properties, rather than using a uniform processing approach. This local optimization ensures stable and accurate pre-distortion for each frequency band while reducing global calculation complexity.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If separate lookup tables are maintained for each frequency band, then the pre-distortion accuracy improves, but the system complexity and memory requirements increase

Engineering Contradiction:
Improvepre-distortion accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores pre-distortion coefficients for each frequency band in separate lookup tables before actual signal processing. This preliminary preparation allows the system to quickly retrieve and apply appropriate coefficients during operation, improving real-time pre-distortion accuracy without increasing runtime calculation complexity or system operational complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates separate lookup tables for each frequency band, which are essentially copies of the pre-distortion coefficient structure tailored to specific frequency characteristics. These copied and adapted lookup tables enable frequency-specific optimization while maintaining a consistent overall system architecture, balancing accuracy improvement with manageable system complexity.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2924938B1Method and system for updating multi-frequency-band pre-distortion coefficient lookup table
Publication Date: 2018.04.04 DATANG MOBILE COMM EQUIP CO LTD
  • EP2924938B1 patent drawingFigure 1~2
  • EP2924938B1 patent drawingFigure 3
  • EP2924938B1 patent drawingFigure 4

AI summary

Disclosed are a method and a system for updating a multi-frequency band pre-distortion coefficient lookup table, in order to solve the problems that the calculation complexity of a multi-frequency band pre-distortion coefficient is high and the calculated pre-distortion coefficient is unstable. Wherein, the method comprises: collecting a first frequency band reference signal and a first frequency band feedback signal, and a second frequency band reference signal and a second frequency band feedback signal; calculating a first frequency band pre-distortion coefficient and a second frequency band pre-distortion coefficient, according to the first frequency band reference signal and the first frequency band feedback signal, and the second frequency band reference signal and the second frequency band feedback signal; performing phase calibration on the first frequency band pre-distortion coefficient and the second frequency band pre-distortion coefficient, respectively; and updating a first lookup table according to the first frequency band pre-distortion coefficient performed the phase calibration, and updating a second lookup table according to the second frequency band pre-distortion coefficient performed the phase calibration. The embodiments of the present application simplify the calculation process, and the calculated pre-distortion coefficient is more accurate.