Software Radio Power Control for Stable RF Amplifier Gain

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Solution Overview

Problem

Existing software radios face challenges in maintaining stable transmission power levels due to the variability of analog power amplifiers, which are influenced by factors like temperature and signal frequency, and existing solutions like calibration tables and power setpoints are either complex or ineffective for complex signals.

Innovation Solution

A software radio system that adjusts the power of the analog signal based on the instantaneous power at the output of the DAC and power amplifier, using a gain setpoint to control a variable attenuator before the power amplifier, allowing for efficient power management even with complex signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a calibration table is provided to address power amplifier variability, then transmission power stability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvetransmission power stabilityVSAvoidcalibration table complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically measuring its own output power and adjusting the power amplifier gain accordingly, eliminating the need for external calibration tables and reducing device complexity while maintaining power stability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A feedback loop continuously monitors the output power of the power amplifier and adjusts the gain setting dynamically to compensate for temperature and frequency variations, replacing static calibration tables with an adaptive control mechanism

Inventive Principle:
Principle #23Feedback

2Device complexity

If power adjustment is based on measured output power and power setpoint, then device complexity is reduced, but effectiveness deteriorates for complex signals with varying power envelopes

Engineering Contradiction:
Improvepower adjustment simplicityVSAvoidpower management effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system pre-calculates the required power amplifier gain based on the known input signal power from the DAC and a desired output power setpoint, adjusting the gain before transmission to accommodate complex signals with varying envelopes without requiring complex real-time measurement and adjustment mechanisms

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides simpler, faster, and less expensive power management, effectively stabilizing transmission power for varying signal envelopes, such as in 4G and 5G communications.

Implementation Method 1

a digital-to-analog converter, DAC, for converting said digital signal into an analog signal

Methodology Applied
Scientific EffectDigital-to-analog conversion:

Data Source

PatentEP4625817A1Software defined radio with improved transmission power management
Publication Date: 2025.10.01 BULL SA
  • EP4625817A1 patent drawingFigure 1~2
  • EP4625817A1 patent drawingFigure 3
  • EP4625817A1 patent drawing

AI summary

The invention relates to a software radio (200) comprising: - at least one processor (104) executing software (102) producing a digital signal representing a data stream to be transmitted, - a digital-to-analog converter, DAC, (106) for converting said digital signal into an analog signal, and - a radiofrequency power amplifier (108) for amplifying the power of said analog signal; said software radio (200) further comprising a unit (206,208) for adjusting the power of the analog signal as a function of: - the instantaneous power of the analog signal at the output of the DAC (106), - the instantaneous power of the analog signal at the output of said power amplifier (108), and - a gain setpoint between said instantaneous powers. It also relates to an electronic device comprising such a digital radio and a method for managing such a software radio.