Segmented Channel Feedback for Contiguous Wi-Fi Beamforming
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Solution Overview
Problem
The amplitude or phase jumps in the V matrix fed back by the station (STA) result in a non-contiguous equivalent frequency domain channel, leading to reduced or negative beamforming gain in Wi-Fi systems using transmit beamforming (TxBF) technology.
Innovation Solution
The method involves sending a frame with segmentation information to the STA, allowing for channel estimation and feedback of right singular matrices in subband channels, followed by interpolation to achieve smooth filtering and increase beamforming gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional channel feedback is used without segmentation, then the feedback process is simple, but the equivalent frequency domain channel becomes non-contiguous and beamforming gain is reduced
Solution Approach 1:
The patent divides the frequency domain channel into multiple subband channels (segments) and processes each segment independently. The access point segments the channel feedback into M subband channels, obtains right singular matrices for each segment, and performs interpolation within each segment to ensure contiguity. This segmentation approach resolves the contradiction by maintaining processing simplicity while achieving contiguous equivalent frequency domain channels that improve beamforming gain.
Solution Approach 2:
The patent performs preliminary channel estimation and right singular matrix acquisition for each subband channel before the actual communication. The access point sends a first frame with segmentation information to the station, enabling the station to perform channel estimation and feedback in advance. This preliminary action ensures that when data transmission occurs, the equivalent frequency domain channel is already prepared to be contiguous, improving beamforming gain without adding complexity to the main transmission process.
2Reliability
If the V matrix is fed back without segmentation, then the feedback overhead is low, but amplitude or phase jumps occur and nearby subcarriers cannot be smoothly filtered
Solution Approach 1:
The patent segments the frequency domain into M subband channels and obtains right singular matrices for each segment separately. This segmentation allows the system to maintain lower feedback overhead by only transmitting necessary segment information while ensuring channel contiguity through proper processing of each segment. The access point performs interpolation on each segment's right singular matrix to eliminate amplitude or phase jumps, achieving smooth filtering without requiring excessive feedback information.
Solution Approach 2:
The patent applies different processing quality to different segments based on their specific characteristics. Each subband channel is processed independently with appropriate interpolation and smoothing applied locally to that segment. This local quality approach ensures that each segment contributes to an overall contiguous equivalent frequency domain channel while avoiding the need to transmit or process the entire channel with uniform high precision, thus balancing contiguity requirements with feedback overhead.
3Productivity
If segmentation is applied to channel feedback, then beamforming gain is improved, but the frame structure and processing become more complex
Solution Approach 1:
The patent introduces segmentation by dividing the channel into M subband channels and processing each segment independently. This segmentation improves throughput by enabling better beamforming gain through contiguous equivalent frequency domain channels. The access point sends a first frame with segmentation information indicating the number of segments, and the station responds with segmented right singular matrices. This structured segmentation approach manages complexity by providing clear guidelines for processing while achieving improved productivity.
Solution Approach 2:
The patent implements a feedback mechanism where the access point sends a first frame with segmentation information to the station, and the station feeds back right singular matrices for each subband channel. This feedback loop enables the access point to adjust and optimize the channel processing based on actual channel conditions. The feedback mechanism manages the increased complexity by providing a systematic way to acquire and process segmented information, ultimately improving throughput through adaptive beamforming.
Data Source
AI summary
An access point (AP) sends a first frame to a station (STA), where the first frame includes at least one of the following segment information: a first segmentation enabling indication and a first segment number M. The first segment number M indicates that an equivalent frequency domain channel corresponds to M subband channels. The AP communicates with the STA based on the at least one piece of segment information.