Multi-AP TXOP Beamforming Coordination with Triggered Feedback
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Solution Overview
Problem
In wireless communication networks, especially in high-density environments, access points (APs) face challenges in coordinating beamforming transmissions due to the lack of a trigger frame before the initial coordinated beamforming physical protocol data unit (PPDU) transmission, leading to synchronization issues and reduced efficiency, which can cause phase misalignment and interference among APs and stations.
Innovation Solution
Implementing coordinated beamforming (CBF) per transmission opportunity (TXOP) frame sequences, where APs exchange messages to synchronize and adjust beamforming patterns, including CBF requests, responses, and triggers, to ensure synchronized and efficient CBF communications among multiple APs and stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple APs transmit CBF PPDU without a trigger frame, then transmission can start immediately, but synchronization issues and phase misalignment occur
Solution Approach 1:
The patent implements a trigger frame mechanism that is exchanged before the actual CBF PPDU transmission. This preliminary action allows APs to synchronize their timing and coordinate their transmissions in advance, ensuring that all APs start their CBF PPDU at the same time. The trigger frame contains synchronization information that resolves the phase misalignment issue while maintaining efficient transmission startup.
2Device complexity
If APs do not exchange synchronization information, then device complexity is reduced, but phase misalignment and beamforming efficiency decrease
Solution Approach 1:
The patent introduces a trigger frame as an intermediary communication mechanism between APs. This trigger frame serves as a mediator that carries synchronization information and coordination data necessary for efficient beamforming. By using this standardized intermediary message format, APs can exchange the necessary synchronization information without requiring complex direct coordination protocols, thus maintaining relatively simple device complexity while achieving high beamforming efficiency.
3Productivity
If APs transmit without coordinated timing, then transmission opportunity is maximized, but interference to unintended devices increases
Solution Approach 1:
The patent merges the timing information and transmission coordination into a unified trigger frame mechanism. By combining synchronization data, timing information, and transmission parameters into this single coordinated framework, multiple APs can transmit simultaneously during their allocated TXOPs without causing interference to unintended devices. The trigger frame ensures that all APs are synchronized and aware of each other's transmission schedules, eliminating harmful interference while maximizing transmission opportunities.
Data Source
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AI summary
The technical solutions are directed to coordinated beamforming per-TXOP frame sequence negotiation. A first access point, AP, (205) can transmit, to a second AP (205) and a first candidate set of stations (240), a first message to initiate transmission opportunity, TXOP, and a CBF request (525). The second AP (205) can transmit a second message to a second candidate set of stations (240) of the second AP (205) identified to participate in the TXOP with a CBF response (530) responsive to the CBF request (525). The first AP (205), responsive to receiving the CBF response (530), can transmit to the second AP (205) a third message having a CBF trigger (545) comprising information to synchronize a CBF transmission to be communicated during the TXOP.