Wireless LAN TXOP Sharing with Triggered AP Time Allocation
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Solution Overview
Problem
Existing wireless LAN systems lack efficient methods for sharing a transmission opportunity (TXOP) between access points, leading to increased latency and inefficient frame exchange operations.
Innovation Solution
A method and apparatus for sharing a TXOP between access points, involving the exchange of trigger frames and physical protocol data units (PPDUs) with stations within allocated time, and setting appropriate Network Allocation Vectors (NAV) to prevent unnecessary blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one access point acquires a transmission opportunity (TXOP) exclusively, then the frame exchange operation is protected and reliable, but other access points cannot share the transmission opportunity leading to increased latency and reduced wireless communication efficiency
Solution Approach 1:
The TXOP acquisition mechanism is segmented into two parts: the triggering access point retains control for frame exchange protection, while time allocation information is distributed to allow other access points to share the transmission opportunity during designated time slots. This segmentation enables both reliability through controlled access and reduced latency through shared transmission opportunities.
Solution Approach 2:
The patent introduces a time dimension to TXOP sharing by allocating specific time slots to different access points within the same transmission opportunity. Instead of exclusive spatial access, multiple access points can operate in the same frequency band at different time intervals, enabling concurrent transmissions that reduce overall latency while maintaining frame exchange protection through temporal separation.
2Reliability
If one access point acquires a transmission opportunity (TXOP) exclusively, then the transmission opportunity is protected from interference, but the device complexity and inefficiency of unused transmission resources increase
Solution Approach 1:
The trigger frame mechanism is enhanced to serve multiple functions: it not only initiates frame exchange operations for the triggering access point but also simultaneously allocates time slots to other access points for TXOP sharing. This multi-functionality reduces the need for separate control mechanisms and simplifies overall TXOP management while maintaining protection through the universal trigger frame protocol.
3Productivity
If transmission opportunities are shared between multiple access points, then wireless communication efficiency is improved and latency is reduced, but the risk of transmission conflicts and interference increases
Solution Approach 1:
The patent implements periodic time slot allocation within TXOP sharing, where access points transmit in alternating or scheduled intervals rather than simultaneously. This periodic structure ensures that each access point has designated transmission windows, reducing conflicts while maintaining high overall efficiency. The regular pattern allows receiving stations to anticipate and properly decode transmissions from different access points.
Data Source
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AI summary
Disclosed are a method and device for sharing TXOP in a wireless LAN system. A method performed by a first AP according to one embodiment of the present disclosure may comprise the steps of: receiving a first trigger frame from a second AP, wherein the first trigger frame includes information about time allocated to the first AP within TXOP obtained by the second AP; and performing transmission or reception of STA and PPDU within the allocated time.