Client Device Location via Network Pairwise Message Exchange

Solution Overview

Problem

Existing indoor positioning methods using wireless local area networks (WLAN) face inefficiencies in measurement rate, data traffic, energy consumption, capacity, and accuracy due to the need for extensive message exchanges and clock synchronization, which results in high data traffic overhead and low positioning accuracy.

Innovation Solution

A method utilizing a pairwise message exchange protocol between network devices with known locations, where each message includes time difference information, allowing client devices to determine their position by listening to these exchanges, thereby reducing data traffic and enhancing measurement rate and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If extensive message exchanges are used for clock synchronization and positioning, then positioning accuracy can be improved, but data traffic overhead increases and measurement rate decreases

Engineering Contradiction:

Improvepositioning accuracyVSAvoiddata traffic overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential time difference information from message exchanges and excludes unnecessary synchronization overhead. By taking out only the critical timing data needed for positioning while eliminating redundant synchronization messages, the system achieves accurate positioning with reduced data traffic overhead.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary clock synchronization between network devices before positioning measurements begin. By pre-synchronizing clocks and establishing time references in advance, the system eliminates the need for continuous synchronization message exchanges during positioning, thereby reducing data traffic overhead while maintaining positioning accuracy.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If multiple message exchanges are performed for positioning measurements, then positioning accuracy improves, but energy consumption increases

Engineering Contradiction:

Improvepositioning accuracyVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential time difference information from message exchanges and excludes unnecessary synchronization overhead. By taking out only the critical timing data needed for positioning while eliminating redundant synchronization messages, the system achieves accurate positioning with reduced data traffic overhead.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary clock synchronization between network devices before positioning measurements begin. By pre-synchronizing clocks and establishing time references in advance, the system eliminates the need for continuous synchronization message exchanges during positioning, thereby reducing data traffic overhead while maintaining positioning accuracy.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If traditional positioning protocols are used with clock synchronization, then positioning can be achieved, but measurement rate is limited and accuracy is reduced

Engineering Contradiction:

Improvemeasurement rateVSAvoidpositioning accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary clock synchronization between network devices before positioning measurements begin. By pre-synchronizing clocks and establishing time references in advance, the system eliminates the need for continuous synchronization message exchanges during positioning, thereby reducing data traffic overhead while maintaining positioning accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic positioning measurements using pre-established time references, allowing measurements to be taken at regular intervals without continuous synchronization overhead. This periodic approach enables high measurement rates while maintaining accuracy through the use of predetermined time references and selective measurement timing.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentEP3544343B1Methods and system for determining a location of a client device, a client device apparatus and a network device apparatus

Publication Date: 2021.11.24 SONY GROUP CORP

Figure 1~2
Figure 3~5
Figure 6~7

AI summary

A method in a wireless network including a client device and at least three network devices, each of the three network devices having a known location comprises a pairwise exchange of messages between at least three different pairs of network devices of said at least three network devices. In the pairwise message exchange a first network device transmits a first message and a second network device receives the first message transmitted from the first network device and transmits a second message to the first network device and the first network device receives the second message transmitted from the second network device and transmits a third message to the second network device, said second and third messages including time difference information of the time difference ΔTk = tk+1 - tk, wherein tk is the time of arrival, ToA, or time of departure, ToD, respectively, of a message at one of the first and second network devices and tk+1 is the ToD or ToA, respectively, of a subsequent message at the other one of the first and second network devices.