RF Sensing Time Reversal for Target Detection and Tracking

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Solution Overview

Problem

The impact of multipath propagation degrades RF sensing applications in wireless communication systems, particularly in urban and indoor environments, leading to challenges in target detection and tracking due to signal power spread and per-channel tap SNR drop, which complicates object detection and tracking performance.

Innovation Solution

Implementing time-reversed RF sensing signals generated based on channel conditions, using time reversal filters to compress multipath channels and enhance SNR for improved target detection and tracking, utilizing network entities for channel estimation and resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional RF sensing signals are transmitted, then the sensing coverage is provided, but multipath propagation degrades the target detection and tracking performance

Engineering Contradiction:

Improvetarget detection performanceVSAvoidmultipath propagation impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies time reversal to the RF sensing signal before transmission. By inverting the temporal sequence of the signal, the multipath components that normally cause degradation are transformed into constructive interference patterns, allowing the signal to focus energy at the target location and improving detection reliability

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful multipath propagation into a beneficial effect. Instead of treating reflected and scattered signals as noise to be eliminated, the time-reversed signal exploits these multipath components to concentrate energy at the target, transforming the previously harmful phenomenon into an asset for enhanced sensing performance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If time-reversed RF sensing signals are transmitted, then target detection performance is improved, but signal processing complexity increases

Engineering Contradiction:

Improvetarget detection precisionVSAvoidsignal processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs time reversal of the RF sensing signal in advance before transmission. This preliminary processing step prepares the signal to automatically focus at the target location through the existing multipath channel, eliminating the need for complex real-time processing during the sensing operation itself

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12416703B2Time reversal for radio frequency sensing

Publication Date: 2025.09.16 QUALCOMM INC

AI summary

Techniques are provided for utilizing time reversed reference signals for radio frequency (RF) sensing operations. An example method for performing radio frequency sensing operations includes transmitting a radio frequency reference signal, receiving channel information associated with the radio frequency reference signal, generating a time reversed radio frequency sensing signal based at least in part on the channel information, and transmitting the time reversed radio frequency sensing signal.