Adaptive Spiral Modulation for Phase-Noise-Resistant QAM Links
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Solution Overview
Problem
Existing modulation methods like QAM and spiral modulation face challenges in high-frequency communication systems due to phase noise, leading to hardware complexity and incompatibility with high spectral efficiency standards, such as 5G.
Innovation Solution
A pseudo-N-order spiral modulation method that simulates a part of M-order QAM symbols, using amplitude and phase weighting parameters to maintain phase noise resistance and spectral efficiency, compatible with existing standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If QAM modulation is used to increase spectral efficiency, then spectrum utilization rate is improved, but phase noise robustness deteriorates
Solution Approach 1:
The invention segments the QAM constellation points into multiple layers (first layer and second layer) with different distances from the origin. The first layer contains constellation points with smaller amplitude (closer to origin) while the second layer contains points with larger amplitude (farther from origin). This segmentation allows the system to use only the first layer under high phase noise conditions, effectively filtering out the impact of phase noise on signal detection.
Solution Approach 2:
Different regions of the constellation diagram are assigned different properties. The first layer constellation points are designed with smaller amplitude and are more robust to phase noise, while the second layer points have larger amplitude for higher spectral efficiency. The system dynamically selects which layer to use based on the measured phase noise level, applying local quality optimization to match channel conditions.
2Productivity
If high frequency bands are used to increase data rate, then productivity is improved, but phase noise interference increases
Solution Approach 1:
The invention introduces dynamic adaptation by continuously monitoring the phase noise level in the channel and dynamically switching between different modulation strategies. When phase noise exceeds a threshold, the system switches to using only the first layer of constellation points or applies phase noise compensation algorithms. This dynamic response allows the system to maintain high data rates when conditions permit while protecting against phase noise when it occurs.
Solution Approach 2:
The system changes the modulation parameter (which layer of constellation points to use) based on channel conditions. By adjusting the effective modulation order and constellation point selection according to measured phase noise characteristics, the system optimizes the trade-off between data rate and reliability in real-time.
3Reliability
If spiral modulation is used to resist phase noise, then phase noise robustness is improved, but compatibility with existing standards deteriorates
Solution Approach 1:
The invention makes the QAM modulation scheme multi-functional by embedding phase noise resistance capabilities within the standard QAM framework. By utilizing the existing QAM constellation structure and adding the dimension of layer selection based on phase noise conditions, the system achieves both standard compatibility and phase noise robustness without requiring a completely different modulation scheme.
Data Source
AI summary
The present disclosure provides a transmitting device, a receiving device and a modulation method. The transmitting device includes: a receiving unit configured to obtain a bit sequence to be transmitted; a control unit configured to perform pseudo-N-order first type of modulation on the bit sequence to be transmitted, according to information about phase noise, wherein 2{circumflex over ( )}N first symbols of the pseudo-N-order first type of modulation correspond to a part of 2{circumflex over ( )}M second symbols of M-order second type of modulation, where M and N are positive integers.