Shared TXOP Scheduling for Coordinated WiFi Station Access
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Solution Overview
Problem
Current WLAN protocols face inefficiencies in channel utilization and increased latency due to contention among stations for TXOP access, particularly in scenarios where non-AP STAs cannot utilize the channel without AP triggers, leading to suboptimal performance in multi-user transmissions.
Innovation Solution
Implementing a mechanism where stations, including AP and non-AP stations, cooperate to share TXOP opportunities in the time domain, allowing stations to share TXOPs with each other without relying on AP triggers, through dynamic, semi-static, and simplified sharing scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional 802.11 protocols are used with AP-level TXOP scheduling, then channel access control is maintained, but channel utilization efficiency deteriorates and latency increases due to contention among stations
Solution Approach 1:
The patent segments the TXOP holder's transmission opportunity into multiple shareable time slots that can be allocated to different stations. The TXOP holder divides its channel access time into portions that can be shared with other stations in the BSS, allowing multiple stations to transmit without re-contending for the channel. This segmentation resolves the contradiction by maintaining controlled access (avoiding contention delay) while improving channel utilization through shared time slots.
Solution Approach 2:
The patent introduces a new dimension of TXOP sharing by allowing stations to share channel access in the time domain beyond traditional AP-controlled UL/DL structures. By enabling non-AP stations to become TXOP holders and share their opportunities with other non-AP stations, the system creates an additional dimension of resource allocation that improves efficiency without requiring AP intervention for every transmission, thereby reducing latency.
2Loss of time
If non-AP STAs must wait for AP trigger frames to access the channel, then centralized control is maintained, but transmission latency increases for time-sensitive applications
Solution Approach 1:
The patent enables non-AP stations to self-organize TXOP sharing among themselves without requiring continuous AP trigger frames. When a non-AP station obtains channel access, it can autonomously share its TXOP with other stations in the group, creating a self-service mechanism that reduces latency for time-sensitive applications while maintaining organized access through pre-established sharing agreements.
3Productivity
If every station competes separately for TXOP access, then channel access fairness is maintained, but channel utilization efficiency deteriorates due to repeated contention
Solution Approach 1:
The patent merges multiple stations' TXOP access requests into a single shared TXOP opportunity. Instead of each station independently contending for channel access, the TXOP holder consolidates multiple transmissions into one shared opportunity, allowing multiple stations to transmit during the same channel occupation. This merging improves channel utilization by eliminating repeated contention while maintaining fair access through coordinated time slot allocation.
Data Source
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AI summary
A wireless local area network (WLAN) protocol allowing a Transmit Opportunity (TXOP) holder, whether its an AP or non-AP STA, to share the TXOP with other stations, that are either AP or non-AP STAs. An intent to share the TXOP is communicated by the TXOP holder either directly or indirectly with other STAs and/or AP, after which scheduling information (time and duration) are shared with the STAs and/or AP. When the TXOP occurs, the STAs and/or AP can access the channel at the time and for the duration specified, thus providing increased use of the TXOP to improve efficiency.