Multi-Link Single-Radio Backoff Control for Frame Collision Avoidance

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Solution Overview

Problem

Enhanced multi-link single radio devices in wireless communication systems face challenges with initial control frame collisions, particularly in wireless local area networks, which can lead to inefficiencies and potential data transmission failures.

Innovation Solution

Wireless devices are configured to detect initial control frame failures due to cross-link collisions and adjust contention windows or modify backoff counter operations to prevent same-link collisions, thereby improving the effectiveness of contention window sizing and reducing the likelihood of simultaneous transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If enhanced multi-link single radio devices operate on multiple links simultaneously, then device capabilities and bandwidth are expanded, but initial control frame collisions increase leading to transmission failures

Engineering Contradiction:
Improvemulti-link operation capabilityVSAvoidinitial control frame transmission reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by detecting the occurrence of a transmit opportunity on one link before attempting transmissions on other links. The device proactively adjusts backoff counter operations based on the detected transmit opportunity timing, preventing same-link collisions before they occur. This advance detection and adjustment mechanism resolves the contradiction by maintaining multi-link operation capability while preventing control frame collisions that would compromise transmission reliability.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If devices use standard backoff counter operations on multiple links, then channel access is simplified, but simultaneous transmissions cause control frame collisions

Engineering Contradiction:
Improvebackoff counter operation simplicityVSAvoidcontrol frame collision
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback by continuously monitoring transmit opportunity occurrences on one link and using this information to adjust backoff counter operations on other links. When a transmit opportunity is detected, the device provides feedback by pausing or discarding backoff counters on other links to prevent simultaneous transmissions. This feedback mechanism maintains operational simplicity while eliminating the harmful effect of control frame collisions through dynamic adjustment based on real-time channel conditions.

Inventive Principle:
Principle #23Feedback

3Device complexity

If contention window size remains fixed, then device operation is straightforward, but transmission efficiency decreases during high collision periods

Engineering Contradiction:
Improvecontention window management complexityVSAvoiddata transmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the contention window size adaptive rather than fixed. The device dynamically adjusts the contention window based on detected transmit opportunity patterns and collision conditions. When collisions are detected or transmit opportunities are frequent, the contention window is modified to optimize transmission timing. This dynamic adjustment resolves the contradiction by improving transmission efficiency during high collision periods while maintaining straightforward operation through automated adaptation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4709023A1Enhanced multi-link single radio in-device cross-link and same-link initial control frame collision avoidance and handling
Publication Date: 2026.03.11 APPLE INC
  • EP4709023A1 patent drawingFigure 1
  • EP4709023A1 patent drawingFigure 2
  • EP4709023A1 patent drawingFigure 3

AI summary

This disclosure relates to methods for handling and avoiding enhanced multi-link single radio in-device cross-link and same-link initial control frame collisions in a wireless local area network. Techniques for handling cross-link collisions can include determining when an enhanced multi-link single radio cross-link collision occurs for a wireless device and selecting a contention window for the wireless device based on the cross-link collision. Techniques for avoiding same-link collisions can include adjusting backoff counter operation on one enhanced multi-link single radio link based on a transmit opportunity that is occurring on another enhanced multi-link single radio link for a wireless device.