Group Delay Error Mitigation in Full Duplex Wireless Positioning

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Solution Overview

Problem

Wireless communication systems face challenges in accurately determining the position of mobile devices due to group delay errors associated with half and full duplex operations, which affect the accuracy of positioning reference signal measurements.

Innovation Solution

The method involves receiving assistance data for downlink and uplink positioning reference signals, determining timing information for half and full duplex modes, performing round trip time message exchanges, and reporting measurement values with indications of the duplex mode to mitigate group delay errors by using differential and double differential round trip time techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full duplex operation is used to enable simultaneous downlink and uplink transmissions, then communication efficiency is improved, but group delay errors increase affecting positioning accuracy

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidpositioning accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the positioning measurement process by identifying and separating measurements taken in half-duplex mode from those taken in full-duplex mode. The location server receives measurement values along with indications of the duplex mode used, allowing it to process and correct full-duplex measurements differently from half-duplex measurements, thereby maintaining positioning accuracy while enabling full-duplex operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter being measured by introducing receive-transmit time difference measurements in addition to traditional timing measurements. By measuring the time difference between receiving a downlink positioning reference signal and transmitting an uplink positioning reference signal, the system can identify and correct group delay errors specific to full-duplex operation, thus maintaining positioning accuracy.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If differential round trip time techniques are applied to correct group delay errors, then positioning accuracy is improved, but system complexity increases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements self-service by having the wireless device autonomously perform receive-transmit time difference measurements and report them along with positioning measurement values. The location server then uses these self-reported differences to automatically correct group delay errors, reducing the need for complex external calibration systems while improving positioning accuracy.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20250008472A1Group delay error mitigation in full duplex modes

Publication Date: 2025.01.02 QUALCOMM INC

AI summary

Techniques are provided for mitigating group delay errors across half duplex and full duplex operations. An example method of performing a round trip time message exchange includes performing the round trip time message exchange with a wireless node including receiving a downlink positioning reference signal and transmitting an uplink positioning reference signal, wherein the round trip time message exchange is associated with at least one duplex mode, and reporting a receive-transmit time difference measurement value based on the round trip time message exchange, wherein the reporting includes an indication of the at least one duplex mode.