TWT Synchronization Across Virtual Access Points
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Solution Overview
Problem
In wireless networks, the existing Target Wake Time (TWT) mechanism struggles to fully realize efficiency gains when stations associated with multiple Virtual Access Points (VAPs) or Basic Service Set Identifiers (BSSIDs) are involved, leading to contention and inefficiencies in scheduling and power management.
Innovation Solution
The proposed solution involves synchronizing TWT agreements across multiple BSSIDs of an access point, allowing stations with similar wake-up characteristics to be grouped for simultaneous or staggered transmission periods, thereby improving spectral efficiency and enabling more efficient Multi-User Multiple Input Multiple Output (MU-MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TWT mechanism is implemented per-VAP basis, then each VAP can independently manage its stations, but stations associated with multiple VAPs experience contention and scheduling inefficiencies
Solution Approach 1:
The patent merges TWT scheduling across multiple VAPs by establishing a master VAP that coordinates wake times for stations associated with multiple VAPs. This consolidation eliminates scheduling conflicts and contention by ensuring synchronized wake times across all VAPs, thereby improving spectral efficiency while maintaining reliable coordination.
Solution Approach 2:
The master VAP acts as an intermediary that receives TWT negotiation information from stations and distributes coordinated wake time schedules back to them. This intermediary role resolves the contradiction by centralizing scheduling authority, ensuring that stations experience no contention regardless of how many VAPs they are associated with.
2Use of energy by moving object
If stations wake up independently for each VAP, then power management can be optimized per-VAP, but overall power consumption increases due to multiple wake events
Solution Approach 1:
The patent combines multiple VAP-specific wake schedules into a single coordinated wake time for stations associated with multiple VAPs. By merging these schedules through the master VAP, stations wake up only once instead of multiple times, reducing both power consumption and time loss while maintaining per-VAP power management optimization.
3Productivity
If multiple VAPs operate with independent TWT schedules, then each VAP can be optimized for its specific traffic patterns, but channel efficiency decreases due to overlapping transmissions
Solution Approach 1:
The patent segments the TWT scheduling function by designating a master VAP that handles cross-VAP coordination while allowing slave VAPs to maintain their specific traffic pattern optimizations. This segmentation enables both channel efficiency through coordinated wake times and VAP-specific adaptability through localized scheduling preferences.
Solution Approach 2:
The patent merges the scheduling authority of multiple VAPs into a single master VAP that coordinates wake times across all VAPs. This merging eliminates overlapping transmissions and improves channel efficiency while preserving VAP-specific optimization capabilities through the coordinated framework.
Data Source
AI summary
The full efficiency gains of the Target Wake Time (TWT) mechanism specified in the 802.11ax standard may not be realized when stations associated to an access point (AP) are spread across multiple Base Station Service Identifiers (BSSIDs). In such a scenario, TWT as conventionally utilized/specified in the 802.11ax standard, cannot properly coordinate sleep/wake schedules for stations due to associating to different BSSIDs. Accordingly, various embodiments are directed to grouping stations associated to multiple BSSIDs of an AP to allow for the synchronization (or staggering) of TWT, and facilitate multi-user transmissions, both in the uplink and downlink directions.