Multi-AP Beamforming Coordination with TXOP Feedback Scheduling
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Solution Overview
Problem
Existing wireless communication systems face challenges in coordinating beamforming between multiple access points due to lack of a trigger frame for Physical Protocol Data Unit (PPDU) transmission, leading to synchronization issues, phase misalignment, and reduced efficiency, especially in high network density scenarios.
Innovation Solution
Implementing coordinated beamforming (CBF) per Transmission Opportunity (TXOP) frame sequence with feedback-based scheduling, where access points exchange messages to synchronize and adjust beamforming parameters based on participant availability and feedback data, ensuring accurate and reliable CBF PPDU transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple access points transmit CBF PPDU without a trigger frame, then transmission can begin immediately, but synchronization issues and phase misalignment occur
Solution Approach 1:
The patent implements preliminary synchronization actions through trigger frames exchanged between access points before CBF PPDU transmission. The trigger frame mechanism allows APs to pre-coordinate timing and phase information, ensuring that when transmission begins, all APs are synchronized. This preliminary coordination resolves the contradiction by preparing the system in advance rather than attempting synchronization during transmission.
Solution Approach 2:
The trigger frame serves as an intermediary mechanism between multiple access points. It carries synchronization information and coordinates the transmission timing of all participating APs. This intermediary enables reliable synchronization without requiring direct peer-to-peer coordination between all AP pairs, resolving the contradiction by introducing a standardized communication protocol for timing coordination.
2Ease of operation
If access points do not exchange feedback data, then the system is simpler to operate, but beamforming efficiency and timing accuracy decrease
Solution Approach 1:
The patent implements feedback mechanisms where access points exchange information about their transmission parameters, timing, and beamforming characteristics. This feedback enables each AP to adjust its transmission to maintain precise synchronization and phase alignment with other APs. The feedback loop resolves the contradiction by automatically optimizing timing precision while maintaining operational simplicity through standardized feedback message formats.
3Device complexity
If access points transmit without coordinating oscillator frequencies, then device complexity is reduced, but phase and amplitude errors increase
Solution Approach 1:
The trigger frame acts as an intermediary that carries frequency offset information and synchronization data between access points. Rather than requiring complex real-time frequency coordination mechanisms, the system uses the trigger frame to communicate necessary frequency adjustment information, enabling accurate phase and amplitude control while keeping device complexity manageable through standardized message exchange.
Data Source
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AI summary
At least one aspect of the technical solutions can be directed to a system. The system can include a first access point, AP, (205) that can be configured to transmit, to a second AP (205) that can be capable of participating in coordinated beamforming, CBF, and a first candidate set of stations (240) of the first AP (205), a first message to initiate transmission opportunity, TXOP. The second AP (205) can be configured to transmit a second message to the first AP (205) and a second candidate set of stations (240) of second AP (205) identified to participate in the TXOP. The second AP (205) can be configured to transmit a third message having a CFB response (530) to the first AP (205). The first AP (205) can be configured to transmit a fourth message to second AP (205) having a CBF trigger (545) that can include information on a preamble of a CBF transmission to be communicated during the TXOP.