Phase Ambiguity Processing for Quadrature Amplitude Modulation Signals
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Solution Overview
Problem
Current methods for addressing phase ambiguity in quadrature amplitude modulation (QAM) signals either increase system overhead or reduce system performance, particularly in high-speed communication systems using SP-QAM and PM-MQAM formats.
Innovation Solution
A phase ambiguity processing method that involves checking for phase ambiguity in QAM signals, performing phase rotation to correct errors, and replacing erroneous signals with corrected ones for decoding, thereby reducing error rates and system overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If training sequence method is used for phase ambiguity detection, then phase ambiguity can be well solved, but system overhead increases
Solution Approach 1:
The patent extracts the phase ambiguity detection function from the traditional training sequence method and implements it through parity check analysis of received symbols. Instead of using dedicated training sequences, the system utilizes the parity check bits embedded in the SP-QAM signal structure to detect phase ambiguity, thereby eliminating the need for separate training sequences and reducing system overhead.
Solution Approach 2:
The system uses its own signal structure (parity check bits in SP-QAM) to perform phase ambiguity detection. The received symbols contain embedded parity information that can be used to detect phase errors without requiring external training sequences, making the system self-sufficient for phase ambiguity resolution.
2Quantity of substance
If phase differential modulation is used to correct phase ambiguity, then system overhead is reduced, but system performance is reduced
Solution Approach 1:
The patent changes the detection parameter from differential phase encoding to parity check analysis. By analyzing the parity relationship between received symbols and known parity check bits, the system can detect phase ambiguity without using differential modulation, thereby maintaining signal quality while reducing overhead.
Solution Approach 2:
The patent introduces parity check analysis as an intermediary mechanism between signal reception and phase correction. Instead of directly using differential modulation, the system first analyzes parity errors to detect phase ambiguity, then applies corrective phase rotation based on the detected error pattern, achieving both overhead reduction and performance maintenance.
3Measurement precision
If differential decoding is performed after parity correction, then parity misjudgement from phase ambiguity occurs, but this leads to large consecutive errors
Solution Approach 1:
The patent performs phase ambiguity detection through parity analysis before differential decoding. By detecting and correcting phase errors in advance using parity check bits, the system prevents phase-induced parity misjudgements from occurring during subsequent differential decoding, thereby avoiding large consecutive errors.
Solution Approach 2:
The system applies preliminary phase correction based on parity error detection before the harmful effect of phase ambiguity can propagate to differential decoding. By counteracting phase errors early in the processing chain, the system prevents the amplification of errors that would otherwise occur during differential decoding.
Data Source
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AI summary
A phase ambiguity processing method and device for a quadrature amplitude modulation signal are provided. The phase ambiguity processing method includes: deciding symbols on a Y polarization state and an X polarization state of a received signal, and mapping to obtain first bit information, where the received signal includes a plurality of first signals; checking and analyzing the first bit information to generate a first check result; judging the first check result to obtain a judgment result as to whether the received signal has phase ambiguity; acquiring at least one of the plurality of first signals in the received signal when the judgment result indicates that the received signal has phase ambiguity; performing phase rotation on the first signal to obtain a second signal; and checking and analyzing the second signal, storing the second signal so that the first signal is replaced with the second signal for decoding processing if a check result is normal. A QAM signal is checked and judged, and error correction is carried out on the QAM signal when the QAM signal has phase ambiguity, such that the error rate of differential decoding of the QAM signal is reduced, system overhead is reduced, and system performance is improved.