Recursive Phase Noise Compensation for DFT-s-OFDM Signals
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Solution Overview
Problem
Phase noise from transmitter and receiver radio frequency local oscillators degrades wireless signals, particularly in millimeter wave communications, leading to reduced signal quality and increased errors in higher order modulations.
Innovation Solution
A phase noise compensation algorithm using recursive phase noise estimation and filtering, combined with pilot sub-symbols, to improve signal quality by compensating for phase noise in DFT-s-OFDM signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase noise compensation is applied to mitigate phase noise degradation, then signal quality is improved, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent applies preliminary action by estimating phase noise using pilot sub-symbols before the main data transmission is processed. The phase noise estimates are obtained from pilot sub-symbols and then used to compensate for phase noise in data sub-symbols, effectively performing the compensation action in advance based on reference signals inserted in the signal structure.
Solution Approach 2:
The patent implements feedback by using the estimated phase noise to correct the received signal. The phase noise estimates derived from pilot sub-symbols are fed back into the system to compensate for phase noise in data sub-symbols, creating a closed-loop correction mechanism that improves signal quality.
2Productivity
If higher order modulations are used to increase data rate, then productivity is improved, but reliability deteriorates due to increased sensitivity to phase noise
Solution Approach 1:
The patent converts the harmful effect of phase noise into a beneficial process by systematically estimating and compensating for phase noise using pilot sub-symbols. This allows higher order modulations to be used reliably, as the phase noise that would normally cause errors is instead used to correct the signal, turning the harmful phase noise into a correctable distortion.
3Measurement precision
If phase noise estimation is performed using all sub-symbols, then measurement precision is improved, but device complexity increases due to additional computational requirements
Solution Approach 1:
The patent applies segmentation by dividing the symbol into separate pilot sub-symbols and data sub-symbols. The phase noise estimation is performed using only the pilot sub-symbols, which are specifically designed for this purpose, while the data sub-symbols are used for actual data transmission. This segmentation allows accurate phase noise estimation without processing all sub-symbols, reducing computational complexity.
Data Source
AI summary
Disclosed is a method for compensating phase noise. A symbol comprising one or more data sub-symbols and one or more pilot sub-symbols is received (501). A sequence of first phase noise estimates is obtained (502) based at least partly on the one or more pilot sub-symbols. A first filter is used to obtain (503, 507) a first sequence of filtered phase noise estimates from at least a subset of the one or more data sub-symbols based at least partly on the sequence of first phase noise estimates. The first sequence of filtered phase noise estimates is stored (506, 510). Phase noise compensation is applied (512) to the one or more data sub-symbols based at least partly on the first sequence of filtered phase noise estimates.