DPD Coefficient Table Switching for Neighbor Cell Interference

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Solution Overview

Problem

Existing Digital Pre-Distortion (DPD) technologies face interference issues with neighbor cells due to inferior pre-distortion coefficients, which affect Adjacent Channel Power Ratio (ACPR) and in-band signal quality, as real-time training data collection is unreliable and often far from previous training values.

Innovation Solution

A method and system that utilize a primary and standby table for pre-distortion coefficients, where the standby table stores updated coefficients, and the power data of processed signals is used to determine if the coefficients are within a setting range, switching between the tables to ensure optimal interference reduction by selecting superior coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If real-time training data collection is used to update pre-distortion coefficients, then the coefficients can be continuously updated, but the reliability of the coefficients deteriorates because the collected data cannot ensure availability and the coefficients are far from previous training values

Engineering Contradiction:
Improvecoefficient update frequencyVSAvoidcoefficient availability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary action by storing multiple historical pre-distortion coefficient sets with timestamps before real-time updates are needed. When updating coefficients, the system first searches for the most recent coefficient set within a valid time range, ensuring reliability before applying updates. This preliminary search and validation step prevents using unreliable coefficients while maintaining continuous update capability.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If inferior pre-distortion coefficients are used for pre-distortion processing, then the processing can continue without interruption, but the Adjacent Channel Power Ratio deteriorates causing serious interference with neighbor cells

Engineering Contradiction:
Improveprocessing continuityVSAvoidinterference with neighbor cells
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system implements feedback by evaluating the ACPR (Adjacent Channel Power Ratio) after applying pre-distortion coefficients. The evaluation module continuously monitors the quality of pre-distortion processing, and when ACPR deteriorates below threshold values, the system automatically triggers a search for better coefficient sets from historical storage or initiates retraining. This feedback loop ensures processing continuity while preventing harmful interference to neighbor cells.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system prepares cushioning measures in advance by storing multiple historical pre-distortion coefficient sets with different timestamps and validity indicators. When the current coefficients start producing harmful interference, these pre-stored alternative coefficient sets serve as immediate backup solutions, allowing the system to switch without interruption and prevent continued interference with neighbor cells.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a primary table and standby table structure is implemented for coefficient storage, then coefficient reliability can be improved through selection, but the device complexity increases

Engineering Contradiction:
Improvecoefficient qualityVSAvoidtable management structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system applies segmentation by dividing the coefficient storage into multiple logically separate tables (primary table, standby table, and historical coefficient sets), each serving specific functions. The primary table stores current valid coefficients, the standby table holds backup coefficients, and historical sets are archived with metadata. This segmentation simplifies management by assigning clear roles to each storage component while maintaining reliability through structured selection based on timestamps and validity flags.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2938034B1Method and system for updating predistortion coefficient
Publication Date: 2018.03.07 DATANG MOBILE COMM EQUIP CO LTD
  • EP2938034B1 patent drawingFigure 1
  • EP2938034B1 patent drawingFigure 2
  • EP2938034B1 patent drawingFigure 3

AI summary

Disclosed is a method and a system for switching pre-distortion coefficients, which is used to solve the problem of interference with neighbor cells due to the inferior pre-distortion coefficients. The method comprises: presetting a primary table and a standby table, wherein the primary table stores default pre-distortion coefficients and the standby table stores updated pre-distortion coefficients; when a data source of a pre-distortion processor adopts the standby table, adopting the updated pre-distortion coefficients to perform parameter output processing to acquire pre-distortion parameters, and conveying the pre-distortion parameters and an input signal to the pre-distortion processor to process to acquire pre-distortion signals; conveying the pre-distortion signals through various signal processors to acquire a first signal, and determining the power data of the first signal; if the power data of the first signal is more than or equal to a setting range, continuing to adopt the standby table as the data source of the pre-distortion processor; and if the power data of the first signal is less than setting range, switching the data source of the pre-distortion processor to the primary table.