Multi-AP Channel Sounding With Bandwidth and Stream Signaling
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Solution Overview
Problem
The challenge of efficiently performing channel sounding in a coordinated multi-AP transmission scenario for WLAN systems, particularly in scenarios where a single access point cannot provide the required number of spatial streams, is not adequately addressed by existing technologies.
Innovation Solution
A method and apparatus for channel sounding that involves a primary access point sending a sounding request frame to a secondary access point, specifying the bandwidth and number of spatial streams for coordinated channel sounding, allowing for efficient joint transmission between multiple access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single access point is used for transmission, then device complexity is reduced, but the quantity of spatial streams is insufficient to meet future WLAN standards
Solution Approach 1:
The patent divides the transmission system into multiple access points, where each AP handles a portion of the spatial streams. This segmentation allows the system to achieve a total of 16 spatial streams through coordinated transmission among multiple APs, rather than requiring a single complex AP to provide all streams independently.
2Quantity of substance
If coordinated multi-AP transmission is implemented, then the quantity of spatial streams increases, but channel sounding coordination becomes complex
Solution Approach 1:
The patent merges the channel sounding procedures of multiple access points into a coordinated process. A trigger frame is designed to simultaneously initiate channel sounding at multiple APs, and the feedback mechanism consolidates channel state information from all participating APs. This merging approach simplifies coordination by providing a unified control and feedback structure rather than managing separate sounding procedures for each AP.
Solution Approach 2:
The patent implements preliminary action by having access points pre-configure their channel sounding parameters based on received trigger frames before actual transmission begins. The trigger frame contains pre-coordinated information about bandwidth, spatial stream allocation, and timing, allowing each AP to prepare its channel sounding procedure in advance, thereby simplifying real-time coordination during actual transmission.
3Ease of manufacture
If channel sounding is performed without coordination, then implementation is simple, but transmission efficiency decreases
Solution Approach 1:
The patent implements a feedback mechanism where each access point reports channel state information back to the system coordinator after performing channel sounding. This feedback enables the system to optimize resource allocation, spatial stream assignment, and transmission parameters based on actual channel conditions, thereby improving transmission efficiency while maintaining relatively simple implementation through standardized feedback procedures.
Data Source
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AI summary
This application discloses a channel sounding method and an apparatus. The method includes the following steps: A first access point device sends a sounding request frame to a second access point device, where the sounding request frame is for requesting the second access point device to perform channel sounding, the sounding request frame includes a sounding bandwidth field and/or a number of spatial streams field, the sounding bandwidth field is used to indicate a bandwidth for performing channel sounding, and the number of spatial streams field is used to indicate a quantity of spatial streams on which channel sounding is performed. Correspondingly, the second access point device receives the sounding request frame sent by the first access point device, and performs channel sounding according to parameter information indicated by the sounding request frame. Implementing this application can enable the first access point device and the second access point device to perform coordinated transmission on a same bandwidth and under scheduling (for example, spatial stream allocation) of the first access point device. This improves efficiency of coordinated transmission between the first access point device and the second access point device.