802.11az FTM Protocol Time Sync Overhead Reduction

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Solution Overview

Problem

The existing 802.11az FTM protocol lacks the capability to efficiently transport 802.1AS-based time synchronization information, which is essential for end-to-end link-independent timing across networks, leading to increased overhead and reduced air-time resources as the number of STAs in a BSS increases.

Innovation Solution

The enhanced FTM protocol system extends the 802.11az Location Measurement Report (LMR) frame to include the 802.1AS Vendor Specific Information Element, enabling the transfer of follow-up information and allowing the requester to indicate the purpose of the FTM Session establishment as TSN-based Time Synchronization, thereby supporting 802.1AS time synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the existing 802.11az FTM protocol is used without extension, then the protocol structure remains simple, but it lacks the capability to transport 802.1AS-based time synchronization information efficiently

Engineering Contradiction:
Improvecapability to transport time synchronization informationVSAvoidprotocol structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the 802.11az FTM protocol with 802.1AS time synchronization information by extending the LMR frame to include a Vendor Specific Information Element. This allows both location measurement and time synchronization functions to be transported through a single unified protocol structure, eliminating the need for separate message exchanges and reducing overall system complexity despite adding multi-functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Loss of information

If traditional time synchronization methods are used separately from FTM, then time synchronization information can be transmitted, but overhead increases and air-time resources are reduced

Engineering Contradiction:
Improvetime synchronization information transferVSAvoidair-time resources
Core Design Contradiction:
Loss of informationVSLoss of energy

Solution Approach 1:

The patent combines time synchronization information transfer with the existing FTM location measurement process by embedding 802.1AS follow-up information within the LMR frame's Vendor Specific Information Element. This merging eliminates the need for separate synchronization message exchanges, thereby reducing protocol overhead and conserving air-time resources while ensuring complete time synchronization information is transmitted.

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If the number of STAs in a BSS increases, then network coverage and capacity improve, but overhead increases and air-time resources are reduced

Engineering Contradiction:
Improvenumber of STAsVSAvoidair-time resources
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent addresses scalability by merging multiple functions (location measurement, time synchronization, and follow-up information transfer) into a single LMR frame exchange. This consolidation means that as the number of STAs increases, each STA participates in the same efficient single-exchange protocol rather than multiple separate exchanges, thereby reducing per-STA overhead and preserving air-time resources even in large-scale deployments.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4362565A1Enhanced FTM protocol to transport time synchronization information
Publication Date: 2024.05.01 INTEL CORP
  • EP4362565A1 patent drawingFigure 1~2
  • EP4362565A1 patent drawingFigure 3
  • EP4362565A1 patent drawingFigure 4

AI summary

This disclosure describes systems, methods, and devices related to enhanced FTM protocol. A device may establish a 802. IAS-based time synchronization. The device may enable a transfer of the 802.1AS follow up information within the 802.11az trigger-based FTM procedure.