Bandwidth-Adaptive Transmitter Power Amplifier Mode Switching

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Solution Overview

Problem

Radio devices face challenges in reducing energy consumption, particularly in power amplifiers, where not all supply power is converted to signal power, leading to inefficiencies and increased heat generation, especially in varying transmission scenarios and bandwidths.

Innovation Solution

A transmitter with a power amplifier that selectively operates in linear or non-linear modes based on allocated bandwidth, using polar modulation for energy efficiency when spectral leakage is within limits and switching to envelope tracking when necessary, with a controller determining the mode based on bandwidth, output power, error vector magnitude, and spectral leakage requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If polar modulation is used to reduce energy consumption, then power efficiency is improved, but spectral leakage increases

Engineering Contradiction:
Improvepower efficiencyVSAvoidspectral leakage
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The transmitter dynamically switches between polar modulation mode and envelope tracking mode based on allocated bandwidth conditions. The controller determines the operating mode in real-time, allowing the system to adapt its power amplification strategy to minimize both energy consumption and spectral leakage under different transmission scenarios

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the power amplifier by switching between two distinct modes: polar modulation (with fixed supply voltage, non-linear operation) for narrow bandwidths where spectral leakage is acceptable, and envelope tracking (with variable supply voltage, linear operation) for wider bandwidths where spectral leakage must be minimized

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If linear mode is used to reduce spectral leakage, then spectral purity is improved, but energy consumption increases

Engineering Contradiction:
Improvespectral leakageVSAvoidenergy consumption
Core Design Contradiction:
Object-generated harmful factorsVSUse of energy by moving object

Solution Approach 1:

The transmitter employs dynamic mode selection where the controller continuously monitors allocated bandwidth and switches between linear (envelope tracking) and non-linear (polar) modes. This dynamic adaptation ensures spectral purity is maintained when bandwidth requires it, while conserving energy when bandwidth is limited

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system varies the supply voltage parameter to the power amplifier: maintaining constant high voltage for polar modulation in narrow bandwidth scenarios, and dynamically tracking the envelope signal for linear operation in wider bandwidth scenarios, thereby optimizing the trade-off between spectral purity and energy consumption

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single operation mode is used for all bandwidths, then device complexity is reduced, but transmission performance deteriorates

Engineering Contradiction:
Improveoperation mode complexityVSAvoidtransmission performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The transmitter is designed with multi-functionality, incorporating both polar modulation and envelope tracking capabilities within a single device. The power amplifier can operate in either mode depending on conditions, making the system universally adaptable to different bandwidth requirements without requiring separate dedicated hardware for each mode

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements dynamic mode switching controlled by a controller that evaluates allocated bandwidth and selects the appropriate operation mode. This dynamic capability allows the transmitter to optimize performance for each specific transmission scenario while maintaining a unified device architecture

Inventive Principle:
Principle #15Dynamics

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 reduces energy consumption by optimizing power amplifier operation, maintaining low energy consumption while minimizing spectral leakage and heat generation, thus improving overall radio device efficiency and performance across different transmission scenarios.

Implementation Method 1

In the second mode, the power amplifier may be adapted to polar modulation operation, and the switch mode voltage converter may be arranged to modulate supply voltage to the power amplifier by an amplitude component of the transmission when in the second mode

Methodology Applied
Scientific EffectPolar modulation: Phase Modulation

Data Source

PatentEP2608415B1Transmitter, transceiver, communication device, method and computer program
Publication Date: 2014.08.27 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2608415B1 patent drawingFigure 1~3
  • EP2608415B1 patent drawingFigure 4~6
  • EP2608415B1 patent drawingFigure 7~9

AI summary

A transmitter comprising a power amplifier, a phase modulator, a switched DC-DC converter, all operating in dual mode, and a controller is disclosed. The power amplifier is arranged to selectively operate either in a first mode or in a second mode, wherein the first mode is a linear mode and the second mode is a non-linear mode in order to save power with least increasing cost in hardware. The transmitter is adapted to operate at different allocated bandwidths, for different radio standards while keeping minimum power consumption governed by the controller. A transceiver, a communication device, a method and a computer program are also disclosed.