PT-RS Cross-Correlation Filtering for NR ICI Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing NR systems face challenges in compensating for inter-carrier interference (ICI) at high frequencies above 52.6 GHz, particularly due to the collision of phase tracking reference signals (PT-RS) with other NR reference signals, and existing methods for ICI estimation are computationally complex and do not effectively suppress ICI.
Innovation Solution
A low-complexity method for direct de-ICI filtering using phase tracking reference signals (PT-RS) positioned in arbitrary subcarriers, allowing for efficient ICI compensation by estimating a de-ICI filter through cross-correlation of PT-RS and adjacent subcarriers, and utilizing multiple NR reference signals for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase tracking reference signals (PT-RS) are positioned on subcarriers to compensate for inter-carrier interference (ICI) at high frequencies, then ICI compensation accuracy is improved, but collision with other NR reference signals occurs and PT-RS overhead increases
Solution Approach 1:
The patent applies partial action by selectively positioning PT-RS only on specific subcarriers where they are most needed for ICI compensation, rather than uniformly across all subcarriers. This allows the system to achieve adequate ICI compensation accuracy while minimizing the quantity of PT-RS resources required, thus reducing overhead and avoiding unnecessary collisions with other reference signals.
Solution Approach 2:
The patent implements local quality by adapting PT-RS positioning to local channel conditions and requirements. Different subcarriers receive PT-RS based on their specific ICI characteristics, allowing precise compensation where needed while avoiding areas where other reference signals are present, thereby reducing overall PT-RS overhead and collision probability.
2Reliability
If existing methods for ICI estimation are used, then ICI compensation is provided, but computational complexity increases and ICI suppression effectiveness decreases
Solution Approach 1:
The patent extracts and isolates the essential components needed for effective ICI compensation, focusing computation only on the critical aspects of ICI estimation rather than attempting to model all channel characteristics. This selective approach maintains suppression effectiveness while significantly reducing computational complexity by eliminating unnecessary calculation steps.
Solution Approach 2:
The patent inverts the traditional approach by first identifying the specific ICI patterns present in the received signal and then designing compensation filters tailored to those patterns, rather than applying generic high-complexity estimation methods. This inversion enables simpler, more targeted computation that achieves better suppression effectiveness with lower complexity.
3Device complexity
If PT-RS are positioned on arbitrary subcarriers for direct de-ICI filtering, then implementation complexity is reduced, but measurement precision for phase noise compensation may deteriorate
Solution Approach 1:
The patent changes the positioning parameters of PT-RS from fixed grid locations to arbitrary subcarrier positions optimized for de-ICI filtering. This parameter change simplifies implementation by allowing flexible placement that avoids collisions with other reference signals, while the cross-correlation-based estimation method maintains measurement precision by adapting to the actual PT-RS positions rather than relying on predetermined grids.
Data Source
AI summary
According to some embodiments, a method performed by a wireless device comprises receiving a wireless signal Rk over all subcarriers allocated to the wireless device. The signal Rk comprises a phase tracking reference signal (PT-RS) on a subset of subcarriers allocated to the wireless device. The method further comprises computing a de-inter-carrier interference (ICI) filter based on a cross correlation of the PT-RS and one or more additional subcarriers and applying the de-ICI filter to the received signal Rk to generate a de-ICI filtered signal.