Multi-AP WLAN Sounding Scheduling for Coordinated Transmissions
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Solution Overview
Problem
Current wireless local area network (WLAN) systems lack a defined protocol for concurrent multi-Access Point (AP) sounding, which is essential for coordinated multi-AP transmission schemes like coordinated orthogonal frequency division multiple access (OFDMA), coordinated spatial reuse (SR), and coordinated beamforming.
Innovation Solution
A method and apparatus for multi-AP sounding procedures in WLAN systems, including coordinated multi-AP transmission schemes, are developed to enable concurrent sounding from multiple APs, utilizing protocols such as coordinated orthogonal frequency division multiple access (OFDMA), coordinated spatial reuse (SR), and coordinated beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If concurrent multi-AP sounding is implemented, then coordinated multi-AP transmission performance is improved, but protocol complexity increases due to lack of defined procedures
Solution Approach 1:
The patent segments the concurrent multi-AP sounding process into distinct phases: (1) coordination setup phase where APs establish coordination agreements, (2) sounding signal transmission phase where each AP transmits sounding signals in designated time slots, and (3) channel state information collection phase where receiving APs gather and process channel state information. This segmentation enables complex coordinated transmissions to be managed through standardized, manageable steps.
Solution Approach 2:
The patent implements preliminary actions by having APs first establish coordination relationships and allocate time slots before actual sounding signal transmission occurs. The coordinating AP pre-configures the sounding schedule and parameters, ensuring that all participating APs are ready for synchronized operation. This preliminary setup eliminates the need for real-time coordination decisions during the sounding process itself.
2Productivity
If multiple APs transmit sounding signals simultaneously, then channel utilization is improved, but interference between APs increases
Solution Approach 1:
The patent divides the sounding transmission timeline into distinct time slots assigned to different APs. The coordinating AP transmits sounding signals in one time slot, while other participating APs transmit in subsequent slots. This temporal segmentation allows multiple APs to conduct sounding operations concurrently without simultaneous transmission interference, maximizing channel utilization while maintaining signal integrity.
Solution Approach 2:
The patent introduces a coordinating AP that acts as an intermediary to manage the sounding process. The coordinating AP allocates time slots, transmits control information, and collects channel state information from all participating APs. This intermediary role enables coordinated operation among multiple APs, allowing them to share the channel efficiently while the coordinator manages interference through centralized scheduling.
Data Source
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AI summary
Methods and apparatuses are described herein for multiple-access point (multi-AP) sounding procedures in a wireless local area network (WLAN). A coordinating AP (CAP) may receive, from one or more member APs in a multi-AP set (MAPS), one or more indications indicating that the one or more member APs are capable of multi-AP sounding during a transmission opportunity (TXOP). The CAP may transmit a CAP TXOP indication (CTI) frame indicating that the multi-AP sounding is to be performed during a TXOP acquired by the CAP. The CAP may receive a CAP TXOP request (CTR) frame indicating that the one or more member APs of the MAP are willing to perform multi-AP sounding during the TXOP. The CAP may transmit a CAP TXOP AP schedule (CTAS) frame indicating a transmission schedule for one or more sounding frames to be transmitted by the one or more member APs during the TXOP.