Channel Sounding Interpolation for Beamforming Matrix Discontinuity
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Solution Overview
Problem
In wireless communication systems, particularly in MU-MIMO environments, discontinuity between beamforming matrixes corresponding to adjacent subcarriers leads to energy loss and increased packet error rates, preventing effective channel smoothing operations.
Innovation Solution
The proposed solution involves an apparatus and method for channel sounding that reduces discontinuity between beamforming matrixes by determining interpolation target subcarriers based on cross correlation values, performing interpolation operations to generate angle information, and providing beamforming feedback to optimize beamforming performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel smoothing operation is performed on received signal, then communication performance may be improved, but discontinuity between beamforming matrixes causes energy loss and increased packet error rate
Solution Approach 1:
The patent performs preliminary detection of discontinuity between adjacent subcarriers before channel smoothing operation. By calculating cross-correlation values and identifying interpolation target subcarriers in advance, the system prepares appropriate handling strategies to prevent energy loss while maintaining communication performance.
Solution Approach 2:
The patent applies different processing strategies to different subcarriers based on their local characteristics. By identifying specific interpolation target subcarriers where discontinuity occurs and applying targeted interpolation operations, the system optimizes each local region rather than applying uniform processing, thereby reducing energy loss while maintaining overall communication performance.
2Reliability
If channel smoothing operation is performed on received signal, then communication performance may be improved, but discontinuity between beamforming matrixes leads to increased packet error rate
Solution Approach 1:
The system performs preliminary identification of interpolation target subcarriers by calculating cross-correlation values between adjacent subcarriers. This advance detection allows the system to apply appropriate interpolation operations before channel smoothing, preventing packet errors that would otherwise occur due to discontinuity.
Solution Approach 2:
The patent applies targeted interpolation operations only to specific interpolation target subcarriers where discontinuity is detected, rather than uniformly processing all subcarriers. This localized approach maintains communication performance while minimizing packet error rates by addressing only the problematic regions.
3Measurement precision
If cross correlation calculation is performed for all subcarriers, then accurate interpolation target identification is achieved, but computational complexity increases
Solution Approach 1:
The patent extracts only the necessary cross-correlation calculations by identifying and processing only interpolation target subcarriers rather than all subcarriers. By taking out the essential operations and eliminating redundant calculations, the system maintains accurate identification while reducing computational complexity.
Solution Approach 2:
The system performs cross-correlation calculations selectively rather than exhaustively for all subcarriers. By applying partial action only to subcarriers that require interpolation based on threshold comparisons, the system achieves sufficient identification accuracy without the excessive computational burden of processing every subcarrier.
Data Source
AI summary
An operating method of a first apparatus, communicating with a second apparatus in a wireless local area network (WLAN) system including the first apparatus and the second apparatus, includes receiving a null data packet (NDP) from the second apparatus, estimating channels corresponding to a plurality of streams of each of a plurality of subcarriers by using the NDP, decomposing singular values of the estimated channels to generate beam steering matrixes corresponding to the plurality of streams of each of the plurality of subcarriers, performing, by stream units, cross correlation between beam steering matrixes corresponding to an adjacent subcarrier of the plurality of subcarriers, determining interpolation target subcarriers, based on cross correlation values corresponding to the plurality of streams of each of the plurality of subcarriers, and generating beamforming feedback, based on the determined interpolation target subcarriers.