SynSIFS Timing Alignment for Multi-Link Frame Exchange Synchronization

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Solution Overview

Problem

Existing wireless communication networks face challenges in synchronizing the end times of frame exchanges across multiple links due to variable frame granularities and lack of mechanisms for synchronizing transmissions, leading to issues like exposed node delays and in-device interference.

Innovation Solution

Implementing a synchronization short inter-frame space (SynSIFS) that allows adjustable duration at a microsecond granularity to align the end of frame exchanges with a target synchronization time, enabling synchronized transmission across multiple links.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If variable frame granularities are used in wireless transmissions, then adaptability and versatility are improved, but synchronization precision deteriorates

Engineering Contradiction:
Improveframe granularity adaptabilityVSAvoidsynchronization precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the time parameter from fixed frame boundaries to flexible sub-symbol granularity. By allowing frame exchanges to end at any sub-symbol boundary within a symbol and introducing SynSIFS with microsecond-level adjustability, the system achieves both adaptability in frame sizing and precision in synchronization timing, resolving the contradiction between variable granularities and synchronization precision.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If synchronized transmission is implemented across multiple links, then network throughput is improved, but device complexity increases

Engineering Contradiction:
Improvenetwork throughputVSAvoidsynchronization mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the initiating device calculate and determine the SynSIFS duration in advance before the frame exchange occurs. This pre-calculation approach allows synchronized transmission across multiple links without requiring complex real-time coordination mechanisms, thereby improving network throughput while keeping device complexity manageable.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If traditional SIFS is used for frame spacing, then ease of operation is maintained, but loss of time increases due to exposed node delays

Engineering Contradiction:
Improveframe spacing simplicityVSAvoidexposed node delay
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent transforms the static, fixed SIFS interval into a dynamic SynSIFS that can be adjusted on a per-frame-exchange basis. This dynamic adjustment allows the system to optimize timing for each specific transmission scenario, reducing exposed node delays and improving time utilization while maintaining operational simplicity through automated calculation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4150870B1Synchronization short inter-frame space (SIFS)
Publication Date: 2025.12.31 QUALCOMM INC
  • EP4150870B1 patent drawingFigure 1
  • EP4150870B1 patent drawingFigure 2A~2B
  • EP4150870B1 patent drawingFigure 3A~3B

AI summary

This disclosure provides methods, devices and systems for synchronizing an end of an exchange of frames during a transmission opportunity (TXOP) with a target synchronization time using a synchronization short inter-frame space (SynSIFS) before a transmission by a wireless communication device that controls the medium. The wireless communication device obtains control of the medium for the TXOP by completing a CCA procedure. An exchange of frames during the TXOP includes transmissions from the wireless communication device and responses from other devices while the wireless communication device controls the medium. A duration of the SynSIFS may be adjustable at a microsecond granularity. Accordingly, the wireless communication device may select a duration of the SynSIFS that allows alignment of the end of the exchange with the target synchronization time. The wireless communication device also may adjust a number of symbols in the transmission from the wireless communication device.