High Bandwidth Modulation via Segmented Envelope and Phase Control
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Solution Overview
Problem
In mobile communication systems, modulators face challenges in achieving high power efficiency and linearity due to the need for quasi-linear amplification, leading to increased costs and inefficiencies, especially when handling non-constant envelope transmission signals.
Innovation Solution
The implementation of a transmission device with a combination of a switched output stage and an error estimation path, including a coding unit for high bandwidth modulation and an error computation unit to estimate and correct inband errors, allowing for efficient amplification and reduced spectral components around the carrier frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a quasi-linear amplifier is used to maintain linearity requirements for non-constant envelope signals, then linearity is improved, but power efficiency deteriorates
Solution Approach 1:
The modulation process is segmented into two independent parts: envelope modulation and phase modulation. The envelope modulator creates a constant envelope signal that is then phase-modulated to carry the actual information. This segmentation allows the power amplifier to operate in a highly efficient non-linear mode while the linearity requirements are met through the phase modulation stage, resolving the contradiction between power efficiency and linearity.
Solution Approach 2:
A phase modulator is introduced as an intermediary between the envelope modulator and the power amplifier. This intermediary transforms the constant envelope signal into a phase-modulated signal that carries the information, allowing the power amplifier to operate efficiently without directly amplifying the non-constant envelope signal, thus maintaining both power efficiency and linearity.
2Reliability
If a quasi-linear amplifier is used to ensure linearity over a wide range of signal levels, then linearity is improved, but device complexity increases
Solution Approach 1:
The amplifier architecture is segmented into a simple high-efficiency power amplifier operating in non-linear mode, with the linearity function separated to the phase modulation stage. This segmentation replaces the complex quasi-linear amplifier architecture with simpler components that collectively achieve the same linearity performance while reducing overall device complexity.
3Productivity
If high bandwidth modulation schemes with non-constant envelope are used, then bandwidth is improved, but power efficiency deteriorates
Solution Approach 1:
The modulation signal is segmented into envelope and phase components. The envelope component is modulated to provide a constant envelope that enables high power efficiency, while the phase component carries the high bandwidth information. This segmentation allows high bandwidth modulation schemes to be used without sacrificing power efficiency, as the power amplifier only needs to amplify the constant envelope signal.
Solution Approach 2:
The modulation approach changes from direct amplitude modulation (which varies envelope and reduces efficiency) to a hybrid approach where the envelope is kept constant and information is encoded in phase. This parameter change in the modulation scheme allows high bandwidth while maintaining constant envelope for power efficiency.
Data Source
AI summary
This disclosure relates systems and methods for a high bandwidth modulation and transmission of communication signals.