APSK Modulation Alternation for PAPR Reduction
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Solution Overview
Problem
Existing modulation schemes face challenges in achieving low peak-to-average power ratio (PAPR) and high data reception quality, particularly in communication/broadcast systems, especially when using error correction codes with high error correction capacity like LDPC and turbo codes, where bit interleaved coded modulation with iterative detection (BICM-ID) techniques are applied.
Innovation Solution
A transmission method that alternately selects 16 amplitude phase shift keying (APSK) modulation schemes with specific constellation arrangements in the I-Q plane, ensuring low PAPR and improved bit labelling to enhance data reception quality, utilizing (12,4)16APSK and (8,8)16APSK modulation schemes with concentric circle configurations and distinct bit labelling strategies to minimize differences between adjacent constellation points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional QAM modulation schemes are used with BICM-ID techniques, then data reception quality can be improved through bit labelling optimization, but application to communication/broadcast systems is limited due to PAPR constraints
Solution Approach 1:
The patent changes the modulation scheme from QAM to APSK modulation, altering the fundamental parameters of the modulation technique. This enables the system to achieve low PAPR characteristics while maintaining compatibility with BICM-ID techniques, thus resolving the contradiction between reception quality improvement and system applicability
Solution Approach 2:
The patent introduces dynamic selection between multiple APSK modulation schemes (different constellation arrangements) based on channel conditions. This dynamic adaptation allows the system to optimize between PAPR reduction and reception quality, making it versatile for various communication/broadcast system scenarios
2Loss of energy
If a single APSK modulation scheme is used, then PAPR can be reduced, but data reception quality deteriorates without optimized bit labelling
Solution Approach 1:
The patent applies different bit labelling strategies to different parts of the constellation diagram. Specifically, different mapping rules are applied to inner circle and outer circle constellation points, optimizing the local bit assignment to minimize error propagation while maintaining low PAPR characteristics
Solution Approach 2:
The patent segments the constellation into multiple groups (inner circle and outer circle) and applies different mapping strategies to each segment. This segmentation allows independent optimization of bit labelling for each group, achieving both PAPR reduction and high reception quality
3Device complexity
If conventional bit labelling is used in APSK modulation, then implementation is simpler, but bit error ratio properties deteriorate
Solution Approach 1:
The patent pre-defines specific bit labelling patterns and mapping rules for APSK constellations before transmission. These predetermined labelling schemes are designed to minimize bit error ratio, and the receiver simply applies the corresponding predetermined rules, avoiding complex real-time optimization while achieving excellent BER performance
Data Source
AI summary
Provided is a transmission method that contributes to an increase in data reception quality when iterative detection is performed at a receive apparatus side. A transmit apparatus alternates between two types of modulation scheme that each shift amplitude and phase, performs mapping to constellation points according to a selected modulation scheme, and transmits a modulated signal obtained by mapping.