Baseband Signal Compensation for GaN Amplifier Memory Effects

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Solution Overview

Problem

Gallium nitride (GaN) power amplifiers exhibit a long-term memory effect that causes millisecond-level distortion, which conventional digital pre-distortion technologies cannot correct, leading to reduced radio frequency indices in base stations.

Innovation Solution

A method involving a computer program product that acquires short-term and long-term powers of a baseband signal, determines a current work status indication signal, and uses a preset matrix lookup table to obtain a multidimensional nonlinear function value for compensating delayed baseband signals, effectively correcting millisecond-level distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional digital pre-distortion technologies are used, then nanosecond-level distortion can be corrected, but millisecond-level distortion caused by long-term memory effect cannot be corrected

Engineering Contradiction:
Improvedistortion correction capabilityVSAvoidtime scale coverage
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the distortion correction task into two distinct parts: short-term distortion correction using conventional digital pre-distortion for nanosecond-level effects, and long-term distortion correction using a separate lookup table-based compensation mechanism for millisecond-level memory effects. This segmentation allows each subsystem to be optimized for its specific time scale without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extends the correction capability from a single time dimension (nanosecond) to multiple time dimensions by introducing a long-term memory effect compensation mechanism that operates on millisecond timescales. The lookup table stores compensation parameters across different time scales, enabling the system to address distortion effects that vary over different temporal dimensions simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If GaN power amplifier is used, then high efficiency and high power density are achieved, but long-term memory effect causing millisecond-level distortion occurs

Engineering Contradiction:
Improvepower densityVSAvoidlong-term memory effect
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing compensation parameters in a lookup table before the actual signal amplification occurs. The system pre-characterizes the long-term memory effects of the GaN power amplifier under various operating conditions and stores the corresponding compensation data, enabling real-time correction without requiring complex real-time calculations during signal processing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary compensation mechanism that acts as a mediator between the input signal and the GaN power amplifier. The lookup table-based compensation system processes the signal beforehand to counteract the anticipated long-term memory effects, effectively isolating the amplifier from its harmful effects through pre-compensation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If long-term memory effect compensation is implemented, then radio frequency index is improved, but system complexity increases

Engineering Contradiction:
Improveradio frequency indexVSAvoidcompensation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses copying by creating a lookup table that stores pre-computed compensation parameters representing the long-term memory effects. Instead of implementing complex real-time mathematical models, the system copies the characteristic behavior of the memory effects into a lookup table, allowing simple table-lookup operations to provide accurate compensation. This significantly reduces computational complexity while maintaining compensation effectiveness.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3678423B1Method and apparatus for compensating for long-term memory effect, and device
Publication Date: 2023.12.13 ZTE CORP
  • EP3678423B1 patent drawingFigure 1
  • EP3678423B1 patent drawingFigure 2
  • EP3678423B1 patent drawingFigure 3~5

AI summary

Disclosed is a method for compensating for long-term memory effect, including: acquiring a short-term power and a long-term power of a baseband signal; obtaining a current work status indication signal according to the short-term power, the long-term power, and a preset threshold range; obtaining an index address according to the current work status indication signal and parameter information; obtaining, from a preset matrix lookup table, a function value corresponding to the index address; and compensating for a delayed baseband signal according to the function value to obtain a compensated baseband signal. Also disclosed are a device and an apparatus for compensating for long-term memory effect.