Adaptive Codebook Beamforming Feedback for Lower WLAN Overhead
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently reducing the overhead of beamforming feedback, which is crucial for improving signal-to-noise ratio (SNR) and reducing retransmissions in Wi-Fi systems.
Innovation Solution
The implementation of a beamformee device that adaptively utilizes a codebook for dual beamforming feedback, employing a processor to generate and feed back wideband and subcarrier beamforming matrices, selected from pre-designed codebooks, to reduce feedback overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional beamforming feedback methods are used, then beamforming can be performed, but feedback overhead is excessive and consumes significant bandwidth
Solution Approach 1:
The patent segments the beamforming feedback process into two distinct stages: wideband beamforming feedback (providing coarse beam directions) and subcarrier beamforming feedback (providing fine beam adjustments). This segmentation allows each stage to transmit only essential information, significantly reducing overall feedback overhead while maintaining beamforming effectiveness across different frequency subcarriers.
Solution Approach 2:
The patent introduces a two-dimensional feedback structure where feedback is provided separately for wideband (frequency-agnostic) and subcarrier-specific (frequency-dependent) beamforming. This dimensional separation allows the system to capture both broad spatial characteristics and frequency-specific variations without transmitting redundant information, thereby reducing feedback overhead while preserving beamforming accuracy.
2Measurement precision
If more beamforming matrices are fed back for higher precision, then SNR improves, but feedback overhead increases
Solution Approach 1:
The patent applies partial action by transmitting only the most critical beamforming information at each feedback stage. Instead of transmitting complete beamforming matrices for all subcarriers, the system transmits wideband beamforming matrices for coarse spatial directions and selective subcarrier beamforming matrices only where frequency variations are significant, achieving adequate precision with reduced overhead.
Solution Approach 2:
The patent performs preliminary wideband beamforming feedback before subcarrier-specific feedback. The wideband feedback establishes coarse beam directions that serve as a foundation for subsequent subcarrier adjustments. This preliminary action allows the system to capture dominant spatial characteristics first, then refine only where necessary, reducing the total amount of precision-critical information that must be transmitted.
Data Source
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AI summary
A beamformee device includes a channel estimator, first and second beamforming matrix providers and a dimension reduction unit. The channel estimator receives a NDP through a channel, and obtains channel information of the channel based on the NDP. The first beamforming matrix provider provides wideband beamforming matrices based on the channel information. The dimension reduction unit generates equivalent channel information based on the wideband beamforming matrices. The second beamforming matrix provider provides beamforming matrices based on the equivalent channel information. The wideband beamforming matrices and the subcarrier beamforming matrices are fed back to the beamformer device. Any one or any combination of the plurality of wideband beamforming matrices and the plurality of subcarrier beamforming matrices are selected from codebooks.