WLAN Channel Access via Poll Frame Offset

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Solution Overview

Problem

In wireless local area network (WLAN) systems, especially with increased numbers of apparatuses in machine-to-machine (M2M) communication scenarios, the existing channel access mechanisms fail to efficiently manage power consumption and interference, leading to suboptimal performance.

Innovation Solution

A method and apparatus for improved channel access in WLAN systems, where a station (STA) transmits a poll frame to an access point (AP) to receive a response frame containing a channel access start offset, allowing for efficient channel access management, power saving, and reduced interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of apparatuses in WLAN system is increased for M2M communication, then communication coverage and network capacity are improved, but power consumption and interference increase

Engineering Contradiction:
Improvenumber of apparatusesVSAvoidpower consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic channel access opportunities where STAs wake up at specific intervals to transmit poll frames and receive data. This periodic action allows STAs to remain in low-power sleep mode between wake-up periods, significantly reducing overall power consumption while supporting numerous M2M devices in the network.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The AP assigns specific channel access start offsets to STAs in advance through poll frames. This preliminary assignment allows STAs to know exactly when to wake up and access the channel, avoiding unnecessary wake-ups and reducing power consumption while maintaining efficient network utilization.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If the number of apparatuses in WLAN system is increased for M2M communication, then communication coverage and network capacity are improved, but interference increases

Engineering Contradiction:
Improvenumber of apparatusesVSAvoidinterference
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent segments the channel access opportunities by assigning different channel access start offsets to different STAs. This segmentation divides the shared medium into time-separated access slots, reducing collisions and interference between multiple M2M devices while maintaining high network capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

STAs access the channel periodically at assigned intervals rather than continuously or randomly. This periodic access pattern reduces interference by ensuring that multiple STAs do not transmit simultaneously, while still allowing high numbers of devices to share the network efficiently.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If existing channel access mechanism is used, then simplicity is maintained, but channel access efficiency and power consumption are suboptimal

Engineering Contradiction:
Improvechannel access mechanismVSAvoidchannel access efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The AP provides feedback to STAs through poll frames, assigning specific channel access start offsets based on current network conditions and STA priorities. This feedback mechanism enables dynamic optimization of channel access efficiency while maintaining relatively simple implementation at the STA side.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The channel access mechanism becomes dynamic through the assignment of variable channel access start offsets to different STAs. This dynamic allocation allows the system to adapt to varying traffic conditions and priority requirements, significantly improving channel access efficiency compared to static mechanisms.

Inventive Principle:
Principle #15Dynamics

4Loss of time

If STAs wake up frequently to check for data, then data reception timeliness is improved, but power consumption increases

Engineering Contradiction:
Improvedata reception timelinessVSAvoidpower consumption
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The AP informs STAs in advance about upcoming data transmissions through poll frames containing channel access start offset information. STAs can then wake up precisely at the assigned time to receive data, ensuring timeliness without needing to wake up frequently or continuously monitor the channel.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of STAs continuously monitoring for data, the system uses a copy mechanism where the AP sends poll frames containing information about upcoming data transmissions. STAs use this information to schedule their wake-up times, achieving timely data reception with minimal power consumption.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2811806B1Method and apparatus for accessing channels in wireless LAN system
Publication Date: 2018.09.05 LG ELECTRONICS INC
  • EP2811806B1 patent drawingFigure 1
  • EP2811806B1 patent drawingFigure 2
  • EP2811806B1 patent drawingFigure 3

AI summary

The present invention relates to a wireless communication system, and more specifically, to a method and apparatus for accessing channels in a wireless LAN system. The method for accessing channels in a station (STA) of the wireless communication system according to one embodiment of the present invention comprises the steps of transmitting a first frame of a channel access request to an access point (AP); and receiving, from the AP, a second frame related to whether access to the channel is allowed in response to the first frame, wherein the second frame can include a value for a channel access start offset with respect to the STA.