STA Channel Measurement Using Idle Sub-Channels to Prevent OBSS Interference

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Solution Overview

Problem

In high-density Wi-Fi deployment scenarios, existing channel measurement methods for next-generation Wi-Fi standards like 802.11ax face interference issues due to the lack of knowledge about occupied channels by surrounding Basic Service Sets (BSS), leading to potential interference with Overlapping Basic Service Sets (OBSS) when Station (STA) devices send sounding reference signals on specified channels without knowing the interference environment.

Innovation Solution

A channel measurement method where the STA receives a measurement notification message from an Access Point (AP), determines idle sub-channels, and sends sounding reference signals using these idle sub-channels to prevent interference with OBSS, ensuring the channel is idle before measurement, thereby minimizing impact on surrounding transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the AP instructs STAs to send sounding reference signals on specific channels for UL channel measurement, then the AP can perform channel measurement to improve scheduling efficiency, but the STAs may send soundings on channels occupied by OBSS, causing interference to surrounding transmissions

Engineering Contradiction:
Improvescheduling efficiencyVSAvoidinterference to OBSS
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The STA performs CCA detection before sending the sounding reference signal to detect whether the channel is idle or occupied. This preliminary action prevents the STA from transmitting on channels currently used by OBSS, thereby avoiding interference while still enabling channel measurement on available channels

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The STA dynamically selects which sub-channels to use for sounding based on CCA detection results. Instead of using all indicated channels, the STA adjusts the set of active measurement channels according to real-time channel availability, changing the transmission parameters adaptively

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the STA performs CCA detection on all sub-channels before measurement, then the STA can identify idle sub-channels to avoid OBSS interference, but the measurement process becomes more complex and time-consuming

Engineering Contradiction:
Improveinterference avoidanceVSAvoidmeasurement process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The channel measurement process is divided into distinct phases: receiving indication information, performing CCA detection on each sub-channel, selecting idle sub-channels, and sending soundings. This segmentation makes the complex process more manageable and systematic

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The STA performs CCA detection on all indicated sub-channels (excessive action) to ensure complete knowledge of channel availability, even though it will only transmit on the subset of idle channels. This ensures no interference occurs while maintaining measurement accuracy on relevant channels

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3316616B1WLAN channel measurement method and station
Publication Date: 2020.04.08 HUAWEI TECH CO LTD
  • EP3316616B1 patent drawingFigure 1~3(a)
  • EP3316616B1 patent drawingFigure 3(b)
  • EP3316616B1 patent drawingFigure 4

AI summary

The present invention provides a channel measurement method and a STA, so as to ensure that a sub-channel on which channel measurement is performed is idle, thereby preventing, to some extent, transmission in an OBSS from being affected by UL channel measurement. The method includes: receiving, by a station STA, a measurement notification message sent by an access point AP, where the measurement notification message carries identifier information of a channel that needs to be measured; and sending, by the STA, a sounding reference signal by using M idle sub-channels, so that the AP measures the M idle sub-channels according to the received sounding reference signal, where the M idle sub-channels are M idle sub-channels determined by the STA from at least one sub-channel included in a channel indicated in the identifier information of the channel that needs to be measured, and M is an integer greater than or equal to 1.