MLINC Outphasing Amplifier for Linear RF Transmission
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Solution Overview
Problem
There is an inherent trade-off between linearity and power efficiency in radio frequency transmitters, which limits the ability to increase data rates and bandwidth in wireless communication.
Innovation Solution
A multilevel linear amplifier with non-linear components (MLINC) using non-isolating outphasing amplifiers and phase modulation to generate discrete amplitude levels, ensuring linear amplification and high bandwidth modulation without amplitude modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If linearity is increased to support high data rates, then data rate is improved, but power consumption increases
Solution Approach 1:
The input signal is segmented into in-phase (I) and quadrature (Q) components, which are processed separately through distinct signal paths. This segmentation allows independent optimization of each path for linearity while using efficient non-linear amplifiers, resolving the contradiction between data rate and power consumption.
Solution Approach 2:
The patent transforms the problem from the time domain to the frequency domain by using phase modulation and spectral shaping. The signal is modulated onto carrier frequencies and processed in the frequency domain, enabling high data rates through efficient spectral utilization while maintaining power efficiency through non-linear amplification.
2Speed
If bandwidth is increased to support high data rates, then data rate is improved, but the trade-off with power efficiency worsens
Solution Approach 1:
The system dynamically adjusts the signal processing parameters including phase modulation depth and spectral shaping coefficients to optimize the trade-off between bandwidth utilization and power efficiency. The adaptive signal paths allow real-time optimization based on channel conditions and data rate requirements.
Solution Approach 2:
The patent changes key signal parameters including phase modulation index, carrier frequencies, and spectral masking functions to achieve high bandwidth utilization. By carefully selecting and adjusting these parameters, the system achieves wide bandwidth operation while maintaining power efficiency through non-linear amplification.
3Loss of energy
If non-linear components are used to improve power efficiency, then power efficiency is improved, but linearity deteriorates
Solution Approach 1:
The patent introduces intermediary signal processing stages including phase modulators and spectral shapers that condition the signal before it reaches the non-linear amplifiers. These intermediaries prepare the signal in a form that is more tolerant to non-linear distortion, allowing efficient amplification while preserving the essential signal characteristics needed for high linearity performance.
Solution Approach 2:
The patent replaces traditional linear amplification mechanisms with non-linear amplification combined with digital signal processing. Instead of using linear analog circuits that consume high power, the system uses non-linear amplifiers with digital correction and processing, substituting mechanical/analog linearity with digital signal processing to achieve both power efficiency and linearity.
Data Source
AI summary
A multilevel linear amplifier with non-linear components, MLINC (1), for a radio frequency transmitter, the MLINC (1) comprising a first outphasing amplifier (2) adapted to receive a first set of input signals (S11, S12) and providing a first intermediate signal (S1) with a stepped envelope depending on a controlled portion (θc1) of a phase modulation in the first set of input signals (S11, S12); a second outphasing amplifier (3) adapted to receive a second set of input signals (S21, S22) and to provide a second intermediate signal (S2) with a stepped envelope depending on a controlled portion (0c2) of a phase modulation in the second set of input signals (S21, S22); and a combiner (6) adapted to combine the first and second intermediate signals (S2) into an output signal (Sout) having an envelope linearized due to a phase symmetry of the first and second intermediate signals (S1, S2).