High-Resolution Doppler Estimation for Non-Uniform TDD Sampling
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Solution Overview
Problem
Existing Doppler estimation techniques in 5G New Radio (NR) time division duplex (TDD) systems face limitations due to uniform and non-uniform sampling, leading to ambiguous mirror artifacts and spectral leakage, hindering the deployment of integrated sensing and communications (ISAC) applications such as vehicular sensing and high-mobility user tracking.
Innovation Solution
A signal processing system utilizing a MUSIC-like algorithm for Doppler region identification and a LASSO-based high-resolution Doppler estimation, which includes preprocessing to normalize non-uniformly sampled signals, followed by eigen-decomposition and low-pass filtering to suppress noise, and then applying LASSO for sparse recovery to enhance velocity estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If uniform sampling is used for reference signals, then sampling consistency is improved, but the maximum detectable velocity is severely limited
Solution Approach 1:
The patent changes the sampling parameter from uniform to non-uniform sampling intervals. By using non-uniform sampling, the system can detect higher velocities without being constrained by the Nyquist criterion limitations of uniform sampling, while still maintaining accurate Doppler estimation through the proposed signal processing methods.
2Speed
If non-uniform sampling is used for reference signals, then maximum detectable velocity is improved, but ambiguity and mirroring artifacts appear in the Doppler spectrum
Solution Approach 1:
The patent extracts and removes the mirroring artifacts and ambiguity from the Doppler spectrum by applying a gating function and signal processing techniques. The method separates the desired signal components from the unwanted artifacts, achieving both high velocity detection and accurate Doppler estimation.
Solution Approach 2:
The patent introduces a gating function as an intermediary element that processes the non-uniformly sampled reference signals. This gating function acts as a mediator that suppresses the mirroring artifacts while preserving the true Doppler components, enabling accurate velocity estimation from non-uniform sampling data.
3Device complexity
If traditional Doppler estimation techniques are used, then system complexity is kept simple, but measurement precision and resolution are insufficient for ISAC applications
Solution Approach 1:
The patent applies preliminary signal processing actions including gating functions and covariance matrix computation before the final Doppler estimation step. These preliminary actions prepare the signal data to enable high-resolution Doppler estimation using methods like MUSIC or ESPRIT, achieving superior measurement precision while managing system complexity through structured processing stages.
Data Source
AI summary
The disclosure described herein generally relates to a system including one or more processors and one or more non-transitory computer-readable media storing instructions that, when executed by the one or more processors, cause the one or more processors to receive a first signal for spectral analysis wherein the first signal is a time division duplex (TDD) signal, apply a MUltiple SIgnal Classification-like (MUSIC-like) algorithm to the first signal to obtain one or more Doppler regions of interest, perform a high-resolution Doppler estimation utilizing Least Absolute Shrinkage and Selection Operator (LASSO) algorithm within the one or more Doppler regions of interest, and output a high-resolution Doppler spectrum for the first signal.