BSS Color Collision Handling in Wireless LAN Power Saving

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Solution Overview

Problem

The limited bits for representing BSS color information in WLAN systems can cause BSS color collisions and malfunction of stations (STA) during power saving operations, leading to inefficient power consumption.

Innovation Solution

A method is introduced where stations (STA) receive information about BSS color disable status from access points (AP), allowing them to enter a doze state only when the BSS color matches their own and the disable status indicates it's not disabled, preventing unnecessary power saving during BSS color collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the STA enters a doze state to save power when receiving frames not intended for it, then power consumption is reduced, but BSS color collisions cause erroneous power saving operations and malfunction

Engineering Contradiction:

Improvepower consumptionVSAvoidSTA operation reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by having the AP pre-announce the BSS color value in beacon frames before actual data transmission. This allows STAs to prepare their BSS color filtering mechanisms in advance, so when frames are received, they can immediately and accurately determine whether to enter doze state or process the frame, preventing erroneous power saving operations due to BSS color collisions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by having STAs continuously monitor and compare the BSS color information in received frames against their own BSS color. This feedback mechanism ensures that STAs can accurately identify whether a frame is intended for their BSS, enabling reliable decision-making for power saving operations while avoiding malfunction due to color collisions

Inventive Principle:

Principle #23Feedback

2Device complexity

If the limited bits for BSS color information are used, then the system complexity is reduced, but BSS color collisions occur with neighboring BSS

Engineering Contradiction:

Improvesystem complexityVSAvoidBSS color uniqueness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the BSS color value parameter based on detection of collisions with neighboring BSS. When a collision is detected, the AP changes the BSS color parameter to a different value, maintaining uniqueness while keeping the bit representation limited. This allows the system to maintain low complexity while ensuring reliable BSS identification

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the BSS color assignment dynamic rather than static. The AP can detect BSS color collisions and reassign different color values to STAs or BSSs as needed. This dynamic approach allows the system to adapt to changing network conditions and avoid collisions while maintaining limited bit representation

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10897737B2Method for reducing erroneous network allocation vector (NAV) updates in wireless LAN system, and device therefor

Publication Date: 2021.01.19 LG ELECTRONICS INC

AI summary

When an AP senses a BSS Color collision with a neighbor BSS in a wireless LAN system, the AP can notify a STA of the collision through information indicating whether the BSS Color is deactivated, and the STA performs intra-PDDU power saving only when the information indicating whether the BSS Color is deactivated does not indicate a deactivation.