Modulation Scheme Switching for Low-PAPR Wireless Signals
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Solution Overview
Problem
High peak-to-average power ratio (PAPR) in quadrature-amplitude modulation (QAM) leads to signal distortion and reduced signal coverage, necessitating a need for signal generation technologies with low PAPR while maintaining spectral efficiency.
Innovation Solution
A coding scheme determining method that dynamically sets thresholds for parameters like modulation order, bandwidth extension, spectral efficiency, and code rate to introduce offset QAMs (OQAMs) for generating signals with low PAPR, ensuring backward compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If QAM modulation is used to achieve high spectral efficiency, then spectral efficiency is improved, but PAPR becomes excessively high causing signal distortion
Solution Approach 1:
The patent applies parameter changes by introducing offset QAM (OQAM) modulation schemes that modify the traditional QAM parameters. Specifically, it changes the modulation order parameter to support both traditional QAM and OQAM modes, allowing dynamic adjustment between high spectral efficiency (QAM) and low PAPR (OQAM) operations. This parameter transformation enables the system to switch modulation types based on channel conditions and requirements.
2Reliability
If average power is reduced to ensure normal signal parsing at receiver, then signal coverage is improved, but power amplifier efficiency decreases
Solution Approach 1:
The patent implements dynamics by enabling dynamic selection between QAM and OQAM modulation schemes based on real-time system conditions. The network device can dynamically adjust the modulation type according to channel quality, signal coverage requirements, and power amplifier operating conditions. This dynamic adaptation allows the system to optimize the balance between signal coverage reliability and power amplifier efficiency in different operational scenarios.
3Object-affected harmful factors
If bandwidth extension is increased to reduce PAPR through spectrum extension, then PAPR is reduced, but frequency resources are occupied and spectral efficiency decreases
Solution Approach 1:
The patent applies parameter changes by modifying the modulation scheme parameter from traditional QAM to OQAM, which inherently provides lower PAPR without requiring bandwidth extension. The invention changes the fundamental modulation parameter structure, allowing the system to achieve PAPR reduction through the offset QAM technique itself rather than through spectrum extension. This parameter transformation eliminates the need to trade off between PAPR reduction and spectral efficiency.
Data Source
AI summary
A coding scheme includes determining a modulation scheme, where the modulation scheme is related to a threshold of a first parameter, and the first parameter includes at least one of: a modulation order, bandwidth extension, scheduled bandwidth, spectral efficiency, a modulation and coding scheme (MCS) index, and a code rate; and sending first indication information to a terminal device, where the first indication information indicates the modulation scheme.