Wireless Receiver Phase Tracking via Autocorrelation
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Solution Overview
Problem
High throughput wireless communication systems operating at high carrier frequencies face significant impairments due to phase noise, which deteriorates signal quality and channel estimation accuracy, particularly in 5G systems where phase variations are more pronounced.
Innovation Solution
A wireless radio receiver is designed to estimate and compensate for phase drift in signal blocks by using a pre-equalization phase tracking unit that computes autocorrelation between initial and terminal signal sequences, interpolates start phases, and generates a phase compensation signal, combined with post-equalization phase tracking to further refine phase compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If oscillators are used to generate sinusoidal signals for up-conversion and down-conversion, then frequency and phase generation is enabled, but phase noise causes phase variations that deteriorate signal quality
Solution Approach 1:
The patent implements feedback by computing autocorrelation between received signal sequences and using the phase information from autocorrelation results to generate phase compensation signals. This feedback mechanism continuously tracks and corrects phase drift, converting the oscillator's phase noise from a harmful effect into correctable information, thereby improving signal quality while maintaining oscillator-based frequency generation
Solution Approach 2:
The patent changes the parameter approach by transitioning from relying on the oscillator's inherent phase stability to actively measuring and compensating phase parameters through autocorrelation. By extracting phase information from signal autocorrelation and applying dynamic phase compensation, the system overcomes the oscillator's phase noise limitation without changing the fundamental oscillation mechanism
2Device complexity
If phase variations are not accounted for correctly, then signal processing is simplified, but channel estimation quality deteriorates and residual phase rotation occurs
Solution Approach 1:
The patent applies preliminary action by performing phase tracking and compensation before equalization and channel estimation processes. The pre-equalization phase tracking unit computes autocorrelation and generates phase compensation signals in advance, removing phase drift effects before the signal enters subsequent processing stages. This preliminary phase correction improves channel estimation quality without significantly increasing overall system complexity, as the phase tracking operates independently in parallel with the main signal path
3Measurement precision
If autocorrelation computation is performed between initial and terminal sequences, then phase drift estimation is enabled, but computational complexity increases
Solution Approach 1:
The patent extracts only the essential phase information from the autocorrelation computation rather than processing the entire signal. By focusing autocorrelation on specific initial and terminal sequences and extracting only the phase component from the autocorrelation result, the system achieves accurate phase drift estimation while minimizing computational complexity. This selective extraction approach computes only what is necessary for phase tracking, avoiding unnecessary computational overhead
Data Source
AI summary
A pre-equalization phase tracking unit, for each signal block of received series: computes autocorrelation between portion of identical-as-transmitted initial and terminal sequences and computes phase of autocorrelation; estimates start phase of block processing window using autocorrelation phase and start phase of previous signal block in series; estimates phase drift within window by interpolating using estimated start phases of at least the signal block and next signal block in series; and computes phase compensation signal using estimated phase drift. A post-equalization phase tracking unit subdivides the block into time sequence of groups of equalized symbols. For each group: compute de-rotated version of each symbol using previous group's accumulated phase to blindly estimate residual group phase; assign group's accumulated phase with sum of group's residual phase and previous group's accumulated phase; estimate phase drift within group by using at least group's accumulated phase to compute phase compensation signal.