Robust Super-Resolution Wireless Ranging via Preliminary Estimates

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Solution Overview

Problem

In wireless communication environments, multipath signals cause interference and degrade performance, making it difficult to determine the covariance matrix and identify line-of-sight signals, especially in time-sensitive applications where repeated measurements are unavailable, leading to underdetermined conditions and errors.

Innovation Solution

An electronic device with an interface circuit that receives wireless signal samples, generates a signal spectrum based on estimated communication parameters, selects a lower parameter with a regression model exceeding a statistical confidence threshold, and identifies line-of-sight signals using eigenvalue decomposition and MUSIC analysis, allowing for accurate determination of communication parameters like time and angle of arrival.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If covariance matrix based high-resolution techniques are used to identify line-of-sight signals, then measurement precision is improved, but device complexity increases and reliability decreases due to underdetermined conditions when data is insufficient

Engineering Contradiction:
Improvetime of arrival estimation precisionVSAvoidcovariance matrix determination reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by using preliminary time-of-arrival estimates obtained through cross-correlation before performing the final super-resolution estimation. These preliminary estimates serve as initial values that guide the subsequent optimization process, allowing the algorithm to converge more reliably even with limited data samples. This preliminary step prepares the system by providing rough estimates that constrain the solution space for the covariance matrix determination.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary optimization process that bridges the gap between preliminary cross-correlation estimates and final super-resolution results. This intermediary step uses the preliminary estimates to initialize and constrain the covariance matrix estimation, acting as a mediator that translates rough preliminary data into reliable final estimates even when direct covariance matrix determination would be underdetermined.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple repeated measurements are acquired to determine the covariance matrix uniquely, then reliability is improved, but loss of time increases due to measurement duration

Engineering Contradiction:
Improvecovariance matrix determination reliabilityVSAvoidmeasurement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent uses preliminary time-of-arrival estimates from cross-correlation to initialize the super-resolution algorithm, eliminating the need for multiple repeated measurements. This preliminary action provides sufficient initial information to proceed with reliable estimation using only a single measurement instance, thereby avoiding the time loss associated with repeated acquisitions while maintaining covariance matrix determination reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the approach from requiring multiple measurements to using a single measurement with optimized processing. By transforming the problem formulation to accept preliminary estimates as input and using constraint-based optimization, the system achieves reliable covariance matrix determination with reduced temporal resources, effectively changing the measurement parameter requirements.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If Fourier techniques are used for time of arrival estimation, then device complexity is reduced, but measurement precision deteriorates when frequency separations are close to Fourier resolution

Engineering Contradiction:
Improvesignal processing complexityVSAvoidtime of arrival estimation precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the signal processing into two distinct stages: a preliminary stage using simple cross-correlation (Fourier-based) to obtain rough time-of-arrival estimates, and a final stage using super-resolution techniques to refine these estimates. This segmentation allows the system to use low-complexity methods first, then apply high-precision methods only where needed, achieving both computational efficiency and measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary time-of-arrival estimation using cross-correlation before applying super-resolution techniques. This preliminary action provides initial estimates that guide the more complex final processing, allowing the system to use simple Fourier-based methods first and then enhance precision only in the critical final estimation step, rather than requiring full high-resolution processing throughout.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10135554B1Robust super-resolution processing for wireless ranging
Publication Date: 2018.11.20 APPLE INC
  • US10135554B1 patent drawing
  • US10135554B1 patent drawing
  • US10135554B1 patent drawing

AI summary

An interface circuit in an electronic device may receive samples of wireless signals in a time interval, where the wireless signals are associated with the second electronic device. Then, the interface circuit may generate, based at least in part on the samples and a number of paths in a channel in a wireless environment of the electronic device, a signal spectrum corresponding to a set of estimated wireless-communication parameters. Moreover, the interface circuit may select a lower wireless-communication parameter in the set of wireless-communication parameters having an associated regression model with a fit to the signal spectrum that exceeds a statistical confidence threshold. Next, the interface circuit may identify, based at least in part on the selected lower wireless-communication parameter, samples of the wireless signal in the wireless signals associated with the line of sight between the electronic device and the second electronic device.