Restricted Access Window Beacon Management in WLAN

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Solution Overview

Problem

Current wireless local area network (WLAN) technologies face inefficiencies in managing power-saving schemes, particularly in infrastructure basic service sets, where stations often wake up unnecessarily during beacon intervals, leading to suboptimal resource utilization and increased power consumption.

Innovation Solution

The introduction of a restricted access window (RAW) mechanism, where an access point defines a window during which stations within the same infrastructure basic service set are not allowed to transmit data frames, allowing only specific types of frames like control, management, and null frames, optimizing the beacon interval for high-priority data transmission and reducing unnecessary wake-ups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If stations wake up for every beacon interval to check for buffered frames, then power consumption is reduced, but resource utilization decreases due to unnecessary wake-ups

Engineering Contradiction:
Improvepower consumptionVSAvoidresource utilization
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The beacon interval is segmented into two distinct phases: a Restricted Access Window (RAW) where only specific frame types are permitted, and a remaining period where normal transmissions occur. This segmentation allows stations to wake up only during the RAW to check for buffered frames via the DTIM, reducing unnecessary wake-ups while maintaining efficient resource utilization during both phases.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If all frame types are allowed during the beacon interval, then transmission flexibility is maintained, but high-priority data transmission efficiency decreases due to interference from lower priority data

Engineering Contradiction:
Improvetransmission flexibilityVSAvoidhigh-priority data transmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The transmission period is divided into a Restricted Access Window (RAW) and a remaining period. During the RAW, only control frames, management frames, and null frames are permitted, creating an interference-free environment for high-priority transmissions. The remaining period allows all frame types including data frames, maintaining overall transmission flexibility while ensuring high-priority data receives dedicated bandwidth without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different frame type restrictions are applied to different time periods within the beacon interval. The RAW imposes strict restrictions allowing only control, management, and null frames, while the remaining period permits all frame types. This local differentiation of transmission qualities optimizes high-priority data transmission during the RAW while maintaining overall network flexibility.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2783544B1802.11 restricted access windows
Publication Date: 2018.06.13 MARVELL WORLD TRADE LTD
  • EP2783544B1 patent drawingFigure 1
  • EP2783544B1 patent drawingFigure 2A~2B
  • EP2783544B1 patent drawingFigure 3A~3C

AI summary

A method of operating an access point includes defining a restricted access window during which stations that belong to a same infrastructure basic service set as the access point are not allowed to transmit data frames. The method further includes generating a beacon announcing the restricted access window, and transmitting the beacon to the stations that belong to the same infrastructure basic service set as the access point. The method also includes, during the restricted access window, receiving a poll frame from a first station of the stations that belong to the same infrastructure basic service set as the access point. The method further includes, subsequent to the poll frame, transmitting a data frame to the first station.