Doherty Wireless Transmitter Switching for Efficient MIMO Back-Off
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Solution Overview
Problem
In wireless communication systems, MIMO transmitters face efficiency degradation and increased power dissipation when operating in non-MIMO mode due to the need for power amplifiers to output higher signal levels, leading to inefficient operation and increased distortion.
Innovation Solution
A wireless transmitter configuration using a Doherty amplifier architecture with two power amplifiers, where one acts as a main amplifier and the other as a sub-amplifier, allowing for efficient operation by adjusting impedance and power distribution between them, thereby reducing power dissipation and maintaining high efficiency across different transmission modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a MIMO transmitter operates in non-MIMO mode using only one transmitting series, then the number of operating circuits is reduced, but the power amplifier must output higher signal levels leading to inefficient operation and increased power dissipation
Solution Approach 1:
The patent applies dynamics by making the impedance of the power amplifier adjustable based on operating mode. The impedance is dynamically changed between a first value for MIMO mode and a second value for non-MIMO mode, allowing the amplifier to operate efficiently in both configurations. This dynamic adaptation resolves the contradiction by enabling high efficiency in non-MIMO mode while maintaining the capability for MIMO operation.
2Power
If a power amplifier outputs higher signal levels to maintain equal received signal strength in non-MIMO mode, then the signal level is sufficient, but the operation efficiency is degraded and distortion increases
Solution Approach 1:
The patent applies parameter changes by modifying the impedance parameter of the power amplifier according to the operating mode. By changing the impedance from a first value to a second value when switching from MIMO to non-MIMO mode, the amplifier can deliver the required high output signal level while maintaining high operation efficiency and avoiding excessive distortion. This parameter adaptation resolves the contradiction between power output and efficiency.
3Adaptability or versatility
If the same power amplifiers are used for both MIMO and non-MIMO modes, then the device is versatile, but the power amplifier operates inefficiently in non-MIMO mode due to back-off operation
Solution Approach 1:
The patent applies dynamics by implementing adjustable impedance control that adapts to different operating modes. The power amplifier dynamically switches between a first impedance value for MIMO mode and a second impedance value for non-MIMO mode, enabling the same amplifier to operate efficiently in both modes without excessive back-off. This dynamic adaptation resolves the contradiction between versatility and energy efficiency.
Data Source
AI summary
There is provided with an amplifier comprising: first and second power amplifiers; a first path configured to output first and second input signals to the first and second power amplifiers; a second path configured to divide a first input signal, output one of divided signals to the first power amplifier and output the other divided signal to the second power amplifier; a first path changeover unit configured to change over the first and second paths; a third path configured to output first and second power amplified signals from the first and second power amplifiers; a fourth path configured to combines a first power amplified signal through an impedance conversion unit from the first power amplifier and a second power amplified signal from the second power amplifier at a combining point and output a combined signal; and a second path changeover unit configured to changeover the third and fourth paths.