Reference AP TSF Alignment for Dense Wireless Networks
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Solution Overview
Problem
Existing methods for time synchronization in wireless networks, particularly in dense environments with multiple access points operating on the same channel, are inefficient and prone to errors due to hidden nodes and overlapping Basic Service Sets (BSSs), which can disrupt the benefits of Reduced Target Wake Time (rTWT) implementations.
Innovation Solution
An enhanced time synchronization system that designates a reference access point or multi-link device to advertise its Timing Synchronization Function (TSF), allowing other access points or devices to align their TSFs, ensuring proper alignment and preventing drift, thereby coordinating Target Wake Time (TWT) or rTWT service periods across multiple access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing time synchronization methods are used in dense wireless networks, then basic time alignment between APs is achieved, but synchronization accuracy deteriorates due to hidden nodes and overlapping BSSs
Solution Approach 1:
The patent introduces a reference AP as an intermediary that centralizes time synchronization coordination. The reference AP receives TSF alignment requests from multiple APs, processes them centrally, and distributes synchronized timing information, thereby eliminating the reliability issues caused by direct peer-to-peer synchronization in dense networks with hidden nodes
Solution Approach 2:
The patent implements a feedback mechanism where APs send TSF alignment requests to the reference AP and receive alignment responses with corrected timing information. This closed-loop feedback system continuously monitors and corrects TSF drift, maintaining high synchronization accuracy despite network density and hidden node interference
2Area of stationary object
If multiple APs operate on the same channel in dense environments, then network coverage is improved, but time synchronization becomes inefficient due to hidden nodes and overlapping BSSs
Solution Approach 1:
The patent segments the dense network into coordination groups, each managed by a reference AP. This segmentation allows independent time synchronization within each group, preventing interference and efficiency degradation that would occur if all APs tried to synchronize simultaneously across the entire dense network
Solution Approach 2:
The reference AP acts as a mediator that coordinates time synchronization for multiple APs within a coordination group. By centralizing synchronization control, the reference AP eliminates the inefficiencies caused by hidden nodes and overlapping BSSs, enabling efficient operation in dense network environments
3Productivity
If TSF alignment is not properly maintained, then network operations continue without interruption, but time drift accumulates and disrupts rTWT benefits
Solution Approach 1:
The patent establishes continuous TSF alignment maintenance through periodic alignment requests and responses between APs and the reference AP. This continuous action prevents time drift accumulation while maintaining uninterrupted network operations, ensuring rTWT benefits are preserved without sacrificing operational continuity
Solution Approach 2:
The patent uses feedback mechanisms where APs continuously monitor their TSF alignment status and send correction requests to the reference AP when drift is detected. This continuous feedback loop maintains precise time alignment without interrupting normal network operations, preserving rTWT performance
Data Source
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AI summary
This disclosure describes systems, methods, and devices related to enhanced time synchronization. A device may define a reference device as a reference access point (AP) or a reference AP multi-link device (MLD). The device may cause to send a TSF alignment request frame to a responder AP to align its TSF with an initiator AP for coordinated target wake time (TWT) or a restricted TWT (rTWT) service periods (SPs). The device may identify a TSF alignment response frame received from the responder AP in response to the TSF alignment request frame.