WLAN Sounding Feedback Aggregation for UL MU-MIMO Interference Mitigation
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Solution Overview
Problem
Existing wireless local area network (WLAN) technologies face inefficiencies in uplink (UL) multi-user (MU) transmission, particularly in mitigating multi-user interference and handling subband-based UL OFDMA transmission, leading to compromised throughput in UL MU-MIMO communications.
Innovation Solution
A sounding procedure that derives channel state information and quality indicators from STAs to the AP, allowing for the determination of optimal transmit beamforming matrices for SU-MIMO or MU-MIMO transmission based on bandwidth and subband usage, and includes feedback frames for efficient resource allocation and interference suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional sequential feedback transmission is used for UL MU sounding, then each user's beamforming feedback can be transmitted individually, but the overall sounding efficiency and throughput are compromised due to increased transmission time and inability to mitigate multi-user interference effectively
Solution Approach 1:
The patent combines multiple feedback frames from different users into a single aggregated feedback frame transmitted simultaneously over the downlink. This merging approach allows the AP to receive beamforming feedback from multiple STAs in parallel rather than sequentially, significantly improving sounding efficiency and reducing the time loss associated with individual feedback transmissions.
Solution Approach 2:
The patent implements a feedback mechanism where STAs transmit beamforming feedback to the AP, which then uses this feedback to optimize downlink MU-MIMO transmissions. The feedback frame contains channel state information that enables the AP to calculate precise beamforming matrices, creating a closed-loop system that continuously improves transmission efficiency based on actual channel conditions.
2Measurement precision
If beamforming feedback is transmitted individually for each user, then feedback accuracy can be maintained, but multi-user interference mitigation is compromised and resource utilization in UL MU-MIMO is inefficient
Solution Approach 1:
The patent introduces an intermediary aggregated feedback frame that consolidates channel state information from multiple users. This intermediary structure allows the AP to process feedback from all users simultaneously and calculate beamforming matrices that account for multi-user interference, rather than processing individual feedback sequences that fail to capture the interactive interference effects between users.
Solution Approach 2:
The patent transforms individual user feedback parameters into a unified aggregated feedback structure that includes channel state information from multiple STAs. By changing the parameter organization from separate individual feedback sets to a consolidated multi-user feedback frame, the system enables joint beamforming optimization that mitigates inter-user interference while maintaining the precision of individual channel measurements.
3Adaptability or versatility
If subband-based UL OFDMA transmission is implemented, then resource allocation flexibility improves, but the complexity of channel state information processing and beamforming matrix determination increases
Solution Approach 1:
The patent segments the frequency spectrum into multiple subbands and processes channel state information separately for each subband. This segmentation allows the system to maintain flexible resource allocation across different frequency regions while managing processing complexity by handling each subband independently, rather than processing the entire bandwidth as a single complex block.
Solution Approach 2:
The patent applies local quality optimization by determining beamforming matrices specific to each subband based on localized channel conditions. Instead of using a single global beamforming approach, the system tailors the beamforming parameters to the specific characteristics of each subband, improving resource allocation flexibility while managing complexity through localized processing rather than global optimization.
Data Source
AI summary
A communication method of the present disclosure comprises transmitting a sounding frame comprising a training signal; and receiving a first feedback frame from a communication partner device, the first feedback frame comprising first beamforming feedback information, wherein the first feedback frame is transmitted together with at least one second feedback frame by multiuser transmission.