Weighted QAM Symbol Decisions for Frequency and Rotation Control
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Solution Overview
Problem
Conventional QAM frequency control methods face challenges in accurately determining carrier frequency and phase, especially during the acquisition phase, leading to erroneous decisions and limited capture range, particularly with high-performance modulations.
Innovation Solution
A device and method for QAM frequency control that utilizes a weighting values device to assign weighting values to symbols based on their position in a complex coordinate space, improving phase offset and rotation control by adapting control parameters and applying these weights to the control loop, thereby enhancing frequency control during the acquisition phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional QAM receivers use standard phase offset control during acquisition phase, then the system can operate with simple control mechanisms, but erroneous symbol decisions occur due to frequency offset and limited capture range
Solution Approach 1:
The patent applies local quality by assigning different weighting values to different symbols based on their position in the complex coordinate space. Symbols that are more reliable indicators of phase offset (e.g., those farther from the origin or in specific quadrants) receive higher weighting values, while less reliable symbols receive lower weights. This selective weighting improves symbol decision accuracy during the acquisition phase without requiring complete redesign of the control mechanism.
Solution Approach 2:
The patent changes the parameter of symbol weighting dynamically during the acquisition phase. By adjusting the weighting values assigned to different symbols based on their positional characteristics in the complex plane, the system optimizes phase offset estimation reliability. This parameter change allows the control mechanism to adapt to varying signal conditions without increasing structural complexity.
2Measurement precision
If the system uses unweighted phase offset control during acquisition phase, then the control structure remains simple, but frequency offset measurement accuracy is limited due to erroneous decisions
Solution Approach 1:
The patent implements local quality by evaluating each symbol's contribution to frequency offset measurement based on its position in the complex coordinate space. Symbols located in regions that provide more accurate phase information (such as those with larger amplitudes or specific angular positions) are assigned higher weighting values. This selective approach improves frequency offset measurement precision by emphasizing reliable measurements while minimizing the impact of erroneous decisions from less reliable symbols.
Solution Approach 2:
The patent creates a weighted version of the phase offset control signal by multiplying individual symbol contributions by their respective weighting values. This weighted copy of the control signal more accurately represents the true frequency offset by giving appropriate emphasis to reliable symbols. The weighting values device generates these multipliers based on symbol positions, effectively creating a corrected representation of phase information without requiring complete system redesign.
3Adaptability or versatility
If conventional receivers treat all symbols equally in phase offset control, then the control algorithm remains simple, but capture range is limited due to constant phase offset errors
Solution Approach 1:
The patent applies dynamics by making the control parameters (weighting values) adaptive rather than fixed. The weighting values change dynamically based on the current symbol positions in the complex coordinate space and the estimated frequency offset. This dynamic adaptation allows the system to adjust to different operating conditions and expand the capture range, as the weighting scheme can optimize performance for various offset conditions rather than being constrained by a fixed equal-weighting approach.
Solution Approach 2:
The patent changes control parameters adaptively during operation. By modifying the weighting values assigned to different symbols based on their positions and the current frequency offset estimates, the system adapts to varying signal conditions. This parameter change mechanism enables the receiver to maintain accurate phase offset control across a wider range of frequency offsets, thereby expanding the capture range without requiring multiple fixed control modes.
Data Source
AI summary
The invention relates to a device and a method for determining a symbol during reception of a signal coupled with a quadrature signal pair having a discriminator for the determination of a symbol with an analysis of a received signal in complex coordinate space, and a control loop for QAM frequency control and/or rotation control while control parameters are used, which are constructed and/or controlled depending on at least one of the symbols to be decided by the discriminator so that the control parameters are adjusted for decisions to be taken later, wherein one weighting device is constructed and/or controlled, providing in each case one weighting value for the symbols to be decided and/or decided by the discriminator among a plurality of weighting values depending on the symbol position in the complex coordinate space for the control loop.