Wireless LAN Beacon Frame RAW Start Time Indication

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Solution Overview

Problem

In wireless LAN systems, especially in M2M communication scenarios with a large number of devices, channel access becomes inefficient due to the lack of effective methods to manage and reduce the size of the beacon frame, which affects the identification of the start time of the Restricted Access Window (RAW), leading to potential collisions and reduced medium utilization.

Innovation Solution

A method and device for performing access in a wireless communication system that involves receiving a frame containing a Restricted Access Window (RAW) Parameter Set (RPS) element, checking the RAW Assignment field, and performing access based on the start time of the RAW, where the start time is determined using the Start Time Indication subfield, allowing the RAW Start Time subfield to be optionally omitted to reduce the size of the beacon frame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the RAW Start Time subfield is always included in the beacon frame, then the start time of RAW can be explicitly indicated, but the beacon frame size increases

Engineering Contradiction:
ImproveRAW start time indication accuracyVSAvoidbeacon frame size
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts the RAW Start Time subfield from the beacon frame structure, making it optional rather than mandatory. The Start Time Indication subfield is introduced to indicate whether the RAW Start Time subfield is present, allowing the system to remove unnecessary data elements while maintaining functionality when needed.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the RAW Start Time subfield dynamic - its presence in the beacon frame is determined by the value of the Start Time Indication subfield. This dynamic structure allows the beacon frame to adapt its size based on whether RAW start time information is currently needed, optimizing the balance between information completeness and frame size.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the beacon frame size is reduced by omitting the RAW Start Time subfield, then transmission efficiency improves, but the complexity of identifying RAW start time increases

Engineering Contradiction:
Improvebeacon frame transmission efficiencyVSAvoidRAW start time identification complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces the Start Time Indication subfield as an intermediary element that mediates between the beacon frame structure and the RAW Start Time subfield. This intermediary provides clear signaling about the presence or absence of the RAW Start Time subfield, simplifying the identification process for receiving devices rather than increasing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter structure by introducing a new control parameter (Start Time Indication subfield) that governs the presence of another parameter (RAW Start Time subfield). This parameter change approach allows the system to maintain flexibility while providing clear, unambiguous signaling that reduces identification complexity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the RAW Start Time subfield is omitted to reduce beacon frame size, then medium utilization improves, but the reliability of RAW start time identification may deteriorate

Engineering Contradiction:
Improvemedium utilization efficiencyVSAvoidRAW start time identification reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism through the Start Time Indication subfield, which provides explicit information back to receiving devices about whether the RAW Start Time subfield is present. This feedback ensures reliable identification by eliminating ambiguity, allowing the system to omit the RAW Start Time subfield when not needed without compromising reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent prepares for potential identification issues by introducing the Start Time Indication subfield in advance. This beforehand cushioning ensures that even when the RAW Start Time subfield is omitted to reduce frame size, the reliability of identification is maintained through the preparatory signaling provided by the indication subfield.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2986076B1Method and device for performing access in wireless LAN system
Publication Date: 2019.02.06 LG ELECTRONICS INC
  • EP2986076B1 patent drawingFigure 1~2
  • EP2986076B1 patent drawingFigure 3
  • EP2986076B1 patent drawingFigure 4

AI summary

One embodiment of the present invention, in a method for enabling a station (STA) to perform an access to a medium in a wireless communication system, is a method for performing an access, comprising the steps of: receiving a frame including an RPS element; checking a restricted access window (RAW) assignment field within the RPS element; and performing an access on the basis of a RAW start time when the STA corresponds to a RAW group related to the RAW assignment field, wherein the RAW start time is obtained on the basis of a start time indication sub field, and the start time indication sub field indicates whether the RAW start time sub field indicating the RAW start time is included in the RAW assignment field.