Shared-Core Multi-Channel Doherty Amplifier for MIMO Consistency

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Solution Overview

Problem

Traditional Doherty power amplifier designs for MIMO transmitters are bulky, inefficient, and costly, with high failure rates due to the need for multiple amplifier cells, leading to poor channel performance consistency and increased complexity as the number of transmitter paths increases, especially in 5G massive MIMO systems.

Innovation Solution

A multi-channel Doherty amplifier design featuring multiple private peaking amplifiers and a shared common Doherty core with a common carrier and peaking amplifier, configured to amplify identical signals for multiple inputs and outputs, allowing for earlier turning on of private peaking amplifiers and optimized power management to improve efficiency and reduce component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional SISO Doherty PA design is used for each transmitter path in MIMO system, then each path can be designed independently, but the system size and complexity increase significantly with multiple amplifier cells

Engineering Contradiction:
ImproveIndependent path designVSAvoidSystem size and complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges multiple independent Doherty amplifier paths into a shared architecture where a common carrier amplifier and common peaking amplifier are shared across multiple transmitter paths. This combining approach reduces the total number of amplifier cells from 6 (traditional 2X2 MIMO) to 4 (one common carrier, one common peaking, and two private peaking), thereby reducing system size and complexity while maintaining independent path functionality through signal routing switches.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common carrier amplifier and common peaking amplifier serve multiple functions by being shared across multiple transmitter paths. These common amplifiers can be dynamically allocated to different paths based on signal requirements, making the amplifier cells universal resources rather than dedicated to single paths, thus reducing overall system complexity.

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

2Adaptability or versatility

If more amplifier cells are used to increase transmitter paths for MIMO, then channel capacity and diversity gain improve, but cost and manufacturing failure rate increase

Engineering Contradiction:
ImproveChannel capacity and diversity gainVSAvoidManufacturing failure rate
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

By merging the carrier and peaking amplifier functions into shared common amplifiers that serve multiple paths, the total component count is reduced. Fewer amplifier cells mean fewer potential failure points and lower manufacturing complexity, thereby improving reliability while maintaining MIMO capabilities through intelligent signal routing.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If traditional Doherty PA is used for high PAPR signal, then efficiency is enhanced, but the Doherty region is limited to maintain high efficiency with signal PAPR greater than 6dB

Engineering Contradiction:
ImprovePower amplifier efficiencyVSAvoidDoherty region range
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent employs dynamic control mechanisms including switching networks and bias control circuits that can dynamically adjust the operating state of amplifier cells. This allows the system to transition between different amplification modes and expand the Doherty region beyond the traditional 6dB limit by adaptively managing power distribution across common and private peaking amplifiers based on instantaneous signal conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3602778B1Multi-channel doherty amplifier, multi-antenna transmitter, and method for turning on the multi-channel doherty amplifier
Publication Date: 2022.11.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3602778B1 patent drawingFigure 1~3
  • EP3602778B1 patent drawingFigure 4(a)
  • EP3602778B1 patent drawingFigure 4(b)~6

AI summary

Embodiments of the disclosure generally relate to a multi-channel Doherty power amplifier, a multi-antenna transmitter, and a method for turning on the multi-channel Doherty amplifier. The multi-channel Doherty power amplifier includes: multiple input ports and the same number of output ports corresponding to multiple channels, the multiple channels having the same characteristics for radio signal amplification and transmission; multiple private peaking amplifiers corresponding to the multiple channels; and a common Doherty core shared by the multiple private peaking amplifiers. The multiple private peaking amplifiers and the common Doherty core are configured to amplify identical multi-channel signal for multiple inputs and multiple outputs, thus higher saving ratio and better channel performance (output power, linearity, efficiency, power gain etc. ) consistency would be greatly improved.