Phase Noise Reduction in Communication Systems
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Solution Overview
Problem
Wireless communication systems face challenges with common phase error and carrier frequency offset, especially at high carrier frequencies, which affect the quality of communication and are difficult to address with existing methods due to high computational complexity and poor performance at low signal-to-noise ratios.
Innovation Solution
A communication system apparatus and method that derotates data symbols by setting the phase rotating angle to zero for the first symbol and then estimates and corrects phase rotations for subsequent symbols using threshold values to reduce the number of samples in the constellation, effectively eliminating phase noise and carrier frequency offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing phase noise reduction methods are used, then phase noise tracking is achieved, but computational complexity increases and performance deteriorates at low signal-to-noise ratios
Solution Approach 1:
The patent extracts only the essential corner samples from the complete symbol constellation for phase rotation estimation. Instead of processing all constellation points, the method selectively uses samples at the corners of the rectangular constellation, which contain sufficient phase information while dramatically reducing the number of computations required for phase noise tracking.
Solution Approach 2:
The patent changes the parameter of sample selection from using all constellation points to using only corner samples. This parameter change in the estimation process reduces computational complexity while maintaining accuracy, as corner samples provide adequate phase rotation information without the overhead of processing the entire constellation.
2Reliability
If existing phase noise reduction methods are used, then phase noise tracking is achieved, but performance deteriorates at low signal-to-noise ratios
Solution Approach 1:
The patent extracts only the essential corner samples from the complete symbol constellation for phase rotation estimation. Instead of processing all constellation points, the method selectively uses samples at the corners of the rectangular constellation, which contain sufficient phase information while dramatically reducing the number of computations required for phase noise tracking.
Solution Approach 2:
The patent applies partial action by using only a subset of constellation samples (the corners) rather than all samples. This partial sampling approach is sufficient for accurate phase rotation estimation and reduces the impact of noise by focusing on the most informative samples, thereby improving performance at low signal-to-noise ratios.
3Measurement precision
If all samples in the constellation are used for phase rotation estimation, then estimation accuracy is maintained, but the number of computations increases
Solution Approach 1:
The patent extracts only the essential corner samples from the complete symbol constellation for phase rotation estimation. Instead of processing all constellation points, the method selectively uses samples at the corners of the rectangular constellation, which contain sufficient phase information while dramatically reducing the number of computations required for phase noise tracking.
Solution Approach 2:
The patent applies partial action by using only a subset of constellation samples (the corners) rather than all samples. This partial sampling approach is sufficient for accurate phase rotation estimation and reduces the impact of noise by focusing on the most informative samples, thereby improving performance at low signal-to-noise ratios.
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
The proposed solution relates to a method and an apparatus in a communication system. The solution comprises receiving (300) as an input a frame comprising of a set of data symbols and reference symbols, each data symbol forming a rectangular symbol constellation of samples, derotating (302) the first symbol of the set on the basis of the reference symbols, and setting (304) phase rotating angle of the first symbol as zero. The solution further comprises for each following successive symbol in the set of symbols: performing (306) equalization; reducing (308) the number of samples in the constellation by selecting samples in two or more corners of the constellation by utilising two or more threshold values; estimating (310) the phase rotating angle of the symbol from the reduced number of samples and derotating (312) the symbol on the basis of the determined phase rotating angle.