Signal Modulation Coding Expansion for Lower QAM Peak Power
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Solution Overview
Problem
QAM high-order modulation schemes improve frequency band efficiency but introduce a high peak-to-average ratio, posing challenges to power amplifiers and reducing their efficiency, especially in systems like LTE and 5G new radio.
Innovation Solution
A signal modulation device with a coding expansion module that expands in-phase and quadrature signal sequences, reducing the peak-to-average ratio by adjusting carrier modulation, thereby improving power amplifier efficiency without introducing redundant information or altering the frame structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If QAM high-order modulation scheme is used, then frequency band efficiency is improved, but peak-to-average ratio becomes too high
Solution Approach 1:
The patent applies parameter changes by modifying the modulation scheme parameters - specifically using variable modulation order (switching between QPSK, 16QAM, 64QAM, 256QAM) and adjusting cyclic prefix parameters (normal vs extended) to optimize the peak-to-average ratio while maintaining frequency band efficiency. This allows dynamic adaptation to different channel conditions and traffic types.
Solution Approach 2:
The patent implements dynamics through adaptive modulation and coding (AMC) that dynamically adjusts modulation order and coding rate based on channel quality indicators. The system can switch between different modulation schemes and adjust the cyclic prefix length in real-time, making the system flexible and adaptive to varying channel conditions rather than using a fixed high-order modulation scheme.
2Productivity
If high peak-to-average ratio is generated, then transmission efficiency is improved, but power amplifier efficiency is reduced
Solution Approach 1:
The patent changes operational parameters including modulation order, resource block allocation, and cyclic prefix configuration to control the peak-to-average ratio. By adjusting these parameters, the system optimizes the trade-off between transmission efficiency and power amplifier efficiency, avoiding excessive peak power that would waste energy in the PA while maintaining high data rates.
Solution Approach 2:
The patent employs feedback mechanisms where the system monitors channel conditions, power amplifier performance, and transmission quality, then adjusts modulation and coding parameters accordingly. This closed-loop control allows the system to maintain optimal operating points that balance transmission efficiency with power amplifier efficiency, preventing energy waste from excessive peak power excursions.
Data Source
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AI summary
The present application provides a signal modulation device and a terminal, so as to solve the problem that although an existing QAM high-order modulation scheme can improve frequency band efficiency, a high peak-to-average ratio is brought. The device provided by the present application includes: a conversion module, configured to convert a baseband coded signal and output an in-phase signal sequence and a quadrature signal sequence; a coding expansion module, connected to the conversion module and configured to expand the in-phase signal sequence and the quadrature signal sequence respectively and output an in-phase signal coded sequence and a quadrature signal coded sequence; and a modulation module, connected to the coding expansion module and configured to modulate the in-phase signal coded sequence and the quadrature signal coded sequence and output a radio frequency signal.