Outphasing Transmitter for Wireless Relay Efficiency
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Solution Overview
Problem
Wireless transmitters face inefficiencies in amplifying RF signals with time-varying amplitudes, leading to higher distortion and lower power efficiency compared to constant amplitude signals, and existing phased array antenna panels struggle to achieve efficient transmission using constant amplitude decomposed RF signals.
Innovation Solution
The implementation of an outphasing transmitter system that decomposes variable amplitude signals into constant amplitude signals before amplification, using separate power amplifiers and antennas to minimize non-linearity and interference, and employs phased array antenna panels with dual-polarized antennas to enhance power efficiency and reduce distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If variable amplitude RF signals are amplified directly, then spectral efficiency is improved, but power efficiency deteriorates and distortion increases
Solution Approach 1:
The variable amplitude RF signal is segmented into two constant amplitude signals through outphasing decomposition. These segmented signals are then amplified separately by individual power amplifiers, allowing each amplifier to operate at high efficiency while the combined output reconstructs the original variable amplitude signal, thus maintaining both spectral and power efficiency.
Solution Approach 2:
The patent transforms the single-dimensional variable amplitude signal into a two-dimensional constant amplitude signal space using outphasing decomposition. By representing the original signal as a sum of two constant amplitude signals with different phases, the system enables efficient amplification in the transformed domain while preserving the information content in the original domain.
2Loss of information
If variable amplitude RF signals are amplified directly, then spectral efficiency is improved, but signal quality deteriorates due to higher distortion
Solution Approach 1:
The variable amplitude RF signal is segmented into two constant amplitude signals through outphasing decomposition. These segmented signals are then amplified separately by individual power amplifiers, allowing each amplifier to operate at high efficiency while the combined output reconstructs the original variable amplitude signal, thus maintaining both spectral and power efficiency.
Solution Approach 2:
The patent introduces outphasing decomposition as an intermediary transformation that converts the difficult-to-amplify variable amplitude signal into easily amplifiable constant amplitude signals. This intermediary step in the signal domain allows high-efficiency amplification while the reconstruction process maintains signal fidelity, thus improving both power efficiency and signal quality.
3Loss of energy
If constant amplitude decomposed RF signals are transmitted using phased array antenna panels, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The constant amplitude decomposed RF signals are transmitted using separate power amplifiers and antenna elements in the phased array. Each amplifier and antenna element operates independently, simplifying the overall system architecture by avoiding the need for complex combining networks while maintaining power efficiency through constant amplitude operation.
Solution Approach 2:
The phased array antenna panel serves multiple functions: it transmits the constant amplitude decomposed RF signals efficiently, performs beamforming for spatial signal control, and enables independent adjustment of each antenna element. This multi-functionality reduces the need for separate dedicated components, thereby managing device complexity while achieving high power efficiency.
Data Source
AI summary
A base station is configured to transmit a substantially unidirectional RF beam to a donor. The donor is in close proximity to a building, and provides communication signals corresponding to the unidirectional RF beam to a relay inside the building. The relay includes a phased array antenna panel having a staggered antenna assignment with predetermined phases for antennas in the phased array antenna panel to produce omnidirectional broad-beam RF signals inside the building.