Pilot-Assisted Receiver Phase Slip Correction During Demodulation
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Solution Overview
Problem
Existing communication systems face performance deterioration due to phase errors and phase slips, particularly in optical communication systems, where differential detection methods suffer from significant signal-to-noise ratio (SNR) degradation compared to synchronous detection.
Innovation Solution
A receiver and transmitter system that incorporates a phase compensation unit and error correction decoding, utilizing pilot sequences for phase slip estimation and correction, enabling iterative decoding to maintain performance akin to synchronous detection even with phase slips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential detection is used to maintain synchronization in optical communication systems, then the system becomes less sensitive to phase fluctuations, but the signal-to-noise ratio deteriorates by approximately 3 dB compared to synchronous detection
Solution Approach 1:
The patent segments the received signal into multiple components: the original received signal, the conjugated signal, and their sum and difference. By processing these segmented signals separately and combining their magnitudes, the system achieves both differential detection's phase fluctuation resistance and synchronous detection's high signal-to-noise ratio performance
Solution Approach 2:
The patent creates a composite detection method that combines elements of both differential detection and synchronous detection. The output is a composite signal formed by summing the magnitudes of multiple processed signal components, achieving performance characteristics that surpass both conventional methods individually
2Loss of energy
If synchronous detection is used to achieve high demodulation performance, then the signal-to-noise ratio is improved, but the system becomes highly sensitive to phase slips and linear phase fluctuations
Solution Approach 1:
The patent applies counter-weight by using the conjugated signal to offset the phase fluctuation effects. By processing both the original and conjugated signals and combining their magnitudes, the system counteracts the harmful effects of phase slips that would otherwise severely degrade synchronous detection performance
Solution Approach 2:
The patent implements feedback through iterative decoding processes that use phase correction information. The system performs initial detection, estimates phase errors, corrects the signals, and repeats the process, with each iteration improving the accuracy and reducing the impact of phase fluctuations
3Measurement precision
If phase compensation methods are applied to correct phase shifts, then the demodulation performance is improved, but the complexity of the receiver increases
Solution Approach 1:
The patent implements self-service phase compensation where the receiver uses its own received signals to generate correction information. By using the received pilot symbols and data symbols themselves to estimate and correct phase errors, the system achieves accurate phase compensation without requiring external reference signals or complex external compensation devices
Data Source
AI summary
A transmitter for transmitting a transmission signal subjected to modulation after error correction coding and a receiver including a phase compensation unit for receiving the transmission signal and performing demodulation therefor while maintaining synchronization thereof and an error correction decoding unit for performing decoding processing for received data that has been subjected to the demodulation. The transmitter transmits a signal formed of a plurality of pilot sequences as a part of the transmission signal, and the receiver has a phase slip estimation processing function for estimating the phase slip by the phase compensation unit by using the plurality of pilot sequences, and for estimating a phase difference component by the error correction decoding unit, to thereby correct a phase of the received data.