Access Point Trigger Frame Recovery for Channel Sounding

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Solution Overview

Problem

In wireless networks, especially those using IEEE 802.11 standards, devices may mistakenly determine that a channel is available for transmission, leading to interference when it is not, due to incorrect channel availability assessments during contention-based access periods.

Innovation Solution

Implementing a method where an access point (AP) transmits a trigger frame to indicate when stations (STAs) should transmit uplink sounding packets during specific periods, and if these packets are not detected, a recovery packet is sent to indicate a busy condition, thereby preventing interference and ensuring channel availability is accurately assessed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If devices use contention-based access to monitor the channel for idle periods before transmission, then channel access efficiency is improved, but devices may mistakenly determine channel availability leading to interference

Engineering Contradiction:

Improvechannel access efficiencyVSAvoidchannel availability assessment accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary channel assessment actions before actual data transmission. The AP sends trigger frames and sounding packets to probe channel conditions in advance, allowing devices to assess channel availability more accurately before committing to transmission, thus preventing premature or incorrect channel access decisions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the AP receives sounding packets from STAs, processes channel state information, and sends recovery packets or acknowledgment frames back to STAs. This feedback loop allows continuous refinement of channel availability assessments and enables the system to adapt to changing channel conditions, reducing mistaken channel availability determinations

Inventive Principle:

Principle #23Feedback

2Productivity

If an access point transmits trigger frames and waits for uplink sounding packets during specific periods, then channel utilization is improved, but interference may occur if packets are not properly detected

Engineering Contradiction:

Improvechannel utilizationVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system takes preliminary anti-action by sending recovery packets when uplink sounding packets are not detected as expected. This counter-measure prevents potential interference by notifying STAs of the busy condition before they attempt transmission, thereby protecting the channel from conflicting transmissions while maintaining high utilization during successful sounding exchanges

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS10686628B2Access point (AP), station (STA) and methods of channel sounding in accordance with contention based access

Publication Date: 2020.06.16 INTEL CORP

AI summary

Embodiments of an access point (AP), station (STA) and method of sounding are generally described herein. The AP may transmit, during a transmission opportunity (TXOP), a trigger frame (TF) to indicate that an STA is to transmit an uplink sounding packet during an uplink sounding period of the TXOP. The AP may attempt to detect the uplink sounding packet during the uplink sounding period. If the uplink sounding packet is not detected during the uplink sounding period, the AP may transmit a recovery packet to cause other STAs to determine a busy condition during the uplink sounding period. If the uplink sounding packet is detected during the uplink sounding period, the AP may determine a channel estimate for the STA based at least partly on the uplink sounding packet.