Access Point CSI Scheduling for Partial MU-MIMO Feedback
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Solution Overview
Problem
In multi-user multiple-input multiple-output (MU-MIMO) wireless networks, particularly in WLANs, some stations (STAs) cannot immediately feed back channel state information due to limited capability or insufficient resources, leading to reduced transmission efficiency and resource waste as the access point (AP) waits for feedback.
Innovation Solution
The AP sends a feedback indication message, high-efficiency long training sequence, and resource scheduling message to schedule STAs for channel state information feedback, allowing them to send acknowledgement messages or partial information initially, and subsequently continues scheduling until complete feedback is achieved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the AP waits for complete channel state information feedback from all STAs before proceeding with transmission, then the accuracy of channel state information is improved, but the transmission efficiency and resource utilization deteriorate due to waiting time
Solution Approach 1:
The patent segments the channel state information feedback process into multiple parts. STAs can provide partial feedback immediately (first feedback information) and continue providing remaining feedback later (second feedback information). This segmentation allows the AP to proceed with transmission using available partial feedback while still receiving complete feedback subsequently, thus resolving the contradiction between waiting for complete feedback and maintaining transmission efficiency.
2Productivity
If the AP schedules multiple STAs for simultaneous feedback, then the resource utilization is improved, but the complexity of coordinating feedback timing and resources worsens
Solution Approach 1:
The patent implements dynamic feedback scheduling where the AP can flexibly adjust which STAs provide feedback and when, based on their capabilities and current system state. The feedback mechanism adapts to different STA types (immediate feedback STAs vs. delayed feedback STAs) and allows the AP to proceed with transmission once minimum feedback is received from critical STAs, rather than requiring synchronized feedback from all STAs. This dynamic approach improves resource utilization while managing coordination complexity through flexible, capability-based scheduling.
Data Source
AI summary
Embodiments of the present invention provide a method and an apparatus for transmitting channel state information. The method includes: sending a feedback indication message, a high-efficiency long training sequence, and a resource scheduling message, wherein the feedback indication message is used to indicate more than one target STAs that need to feed back channel state information, the high-efficiency long training sequence is used for determining the channel state information by the target STAs, and the first resource scheduling message is used to indicate a communication resource used by the target STAs when the target STAs feed back the channel state information; and receiving the channel state information sent by the target STAs by using the communication resource.