Primary Link Identification in NSTR Multi-Link Wireless Systems

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Solution Overview

Problem

In wireless communications under IEEE 802.11 standards, multi-link devices face interference issues when operating on multiple links close to each other, preventing simultaneous transmission and reception, and there is a need for identifying primary and non-primary links in non-simultaneous-transmission-and-reception link pairs, especially for non-AP MLDs associating with NSTR AP MLDs.

Innovation Solution

The proposed solution involves AP MLDs transmitting beacon frames with indications of their affiliation with NSTR AP MLDs and operation on primary links, using subfields in Multi-Link elements and Reduced Neighbor Report elements to identify primary and non-primary links, allowing non-AP STAs to determine the NSTR link pairs through decoding specific subfields and bitmaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an MLD operates on multiple links with IDC interference, then multi-link operation capability is improved, but simultaneous transmission and reception cannot be supported on both links

Engineering Contradiction:
Improvemulti-link operation capabilityVSAvoidIDC interference
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the multi-link operation by designating one link as primary and another as non-primary, creating distinct operational roles for each link to manage IDC interference. The primary link handles general operations while the non-primary link is restricted to specific transmission scenarios, thereby dividing the operational burden and reducing interference conflicts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by imposing different operational constraints on different links within the same MLD. The primary link operates with standard permissions while the non-primary link operates under restricted conditions (only when primary link STA is TXOP holder), tailoring the operational characteristics of each link to its specific role in managing IDC interference.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If a non-AP MLD associates with an NSTR AP MLD, then association capability is improved, but the non-AP MLD needs to identify primary and non-primary links which is not currently defined

Engineering Contradiction:
Improveassociation capabilityVSAvoidprimary link identification
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements preliminary action by having the AP MLD pre-configure and indicate the primary link designation through beacon frames before the non-AP MLD attempts association. This advance information provision allows the non-AP MLD to identify the primary link without complex real-time detection, simplifying the association process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses beacon frames as an intermediary carrier to transmit primary link identification information from the AP MLD to the non-AP MLD. This intermediary mechanism facilitates the exchange of critical identification data without requiring direct complex interaction or additional signaling protocols between the devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If synchronous transmission is applied between NSTR AP MLD and STR/NSTR non-AP MLD, then IDC interference is avoided, but contention-based channel access on NSTR link pair is required

Engineering Contradiction:
ImproveIDC interference avoidanceVSAvoidcontention-based channel access coordination
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the non-primary link's transmission permissions dynamic rather than static. The non-primary link STA can transmit only when the primary link STA is a TXOP holder, creating a dynamic permission system that adapts to real-time channel conditions and transmission states, thereby coordinating synchronous transmission while managing contention access.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4333548A1Primary link identification schemes in wireless communications
Publication Date: 2024.03.06 MEDIATEK INC
  • EP4333548A1 patent drawingFigure 1
  • EP4333548A1 patent drawingFigure 2
  • EP4333548A1 patent drawingFigure 3

AI summary

Various techniques and schemes pertaining to primary link identification schemes in wireless communications are described. An access point (AP) multi-link device (MLD) establishes a plurality of links, the plurality of links comprising a primary link and a non-primary link that constitute a non-simultaneous-transmission-and-reception (NSTR) link pair. An AP affiliated with the AP transmits a beacon frame with an indication on whether or not the AP or a reported AP is affiliated with an NSTR AP MLD and is operating on the primary link of the NSTR link pair.