Aggregated CSI Feedback for Multi-AP Joint Transmission
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Solution Overview
Problem
Existing sounding protocols in wireless communication systems using access point collaboration result in insufficiently accurate channel estimation, necessitating an improved method for determining channel state information (CSI).
Innovation Solution
A method for determining CSI by receiving and aggregating sounding data transmissions from multiple access points (APs) over various communication channels, transforming the aggregated channel matrix using singular value decomposition (SVD) to produce Σ and V matrices, and transmitting these matrices back to the APs for precoder computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing sounding protocols are used with AP collaboration, then the system can support multi-AP coordination, but the channel estimation accuracy becomes insufficient
Solution Approach 1:
The patent segments the CSI feedback process by separating the aggregation of channel estimates from the singular value decomposition (SVD) operation. The STA first aggregates channel estimates from multiple APs, then performs SVD on the aggregated matrix. This segmentation allows for more accurate channel estimation by properly combining multi-AP channel information before extracting singular values, thereby improving CSI measurement accuracy while maintaining reliability of the sounding protocol
Solution Approach 2:
The patent introduces a new dimension to the CSI feedback process by aggregating channel estimates across multiple APs in the spatial domain before performing SVD. Instead of processing each AP's channel estimate independently and then combining results, the method creates an aggregated channel matrix that incorporates spatial information from all APs simultaneously. This dimensional aggregation in the spatial domain improves channel estimation accuracy by capturing the joint spatial characteristics of multi-AP transmissions
2Productivity
If multiple APs transmit sounding data concurrently, then the throughput increases, but the channel estimation accuracy deteriorates due to interference
Solution Approach 1:
The patent implements a feedback mechanism where the STA receives sounding packets from multiple APs, aggregates the channel estimates, performs SVD to extract singular values and vectors, and feeds back the aggregated CSI to the APs. This feedback loop enables the system to adapt to the combined channel conditions from multiple APs, improving channel estimation accuracy even when APs transmit concurrently by providing corrected CSI information that accounts for multi-AP interference and spatial characteristics
Data Source
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AI summary
A method of determining channel state information (CSI) of a wireless channel by a STA includes receiving a plurality of sounding data transmissions from a plurality of APs over a plurality of communication channels. It further includes estimating, for each of the communication channels, channel state information (CSI) of the channel based on plurality of sounding data transmissions received over each of the communication channels. In addition it includes aggregating the channel state information of each of the communication channels to produce an aggregated CSI and transmitting the aggregated CSI to the plurality of APs.