Channel Correlation User Detection in 802.11 Uplink MIMO
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Solution Overview
Problem
In 802.11 WLANs, especially in uplink multi-user MIMO transmissions, when a client station fails to respond to a trigger frame, the wireless access point incorrectly assumes data reception from all stations, leading to inaccurate decoding and performance degradation due to the inclusion of noisy channels in the channel matrix.
Innovation Solution
A method and system for detecting client stations based on channel correlation, where trigger frames are transmitted to initiate uplink transmission, and a channel matrix is determined to generate correlation indicators. Non-responsive client stations are identified by comparing correlation values, and their corresponding columns are removed from the channel matrix to improve decoding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the wireless access point assumes data reception from all client stations indicated in the trigger frame, then the decoding process can be performed without additional detection steps, but the decoding accuracy deteriorates due to inclusion of noisy channels from non-responsive stations
Solution Approach 1:
The patent applies preliminary action by performing channel correlation analysis before the decoding process. The access point calculates correlation indicators for each client station based on received uplink data signals and channel coefficients, identifying non-responsive stations in advance. This allows the system to remove noisy channels from the channel matrix before decoding, improving accuracy without adding complexity to the main decoding workflow.
2Reliability
If the wireless access point includes all client stations in the channel matrix for decoding, then the processing is simpler without removal operations, but the reliability of the reception process deteriorates due to noisy channel interference
Solution Approach 1:
The patent applies the extraction principle by removing columns corresponding to non-responsive client stations from the channel matrix. After calculating correlation indicators and identifying stations that failed to respond, the system extracts and removes their associated channel columns from the matrix before performing decoding operations. This eliminates noisy channel interference and improves reception reliability while maintaining efficient processing.
3Measurement precision
If the wireless access point performs channel correlation analysis for each client station, then the user detection accuracy improves, but the computational complexity increases
Solution Approach 1:
The patent applies self-service by utilizing the existing uplink data signals and channel coefficients that are already being processed for normal reception. The channel correlation analysis leverages these existing measurements to automatically identify non-responsive stations without requiring separate detection signals or additional processing resources. The system serves its own detection needs using data already collected for primary communication functions.
Data Source
AI summary
Embodiments described herein methods and systems for channel correlation based user detection in an uplink multiuser transmission of a multiple-input multiple-output (MIMIO) network. In some embodiments, the channel correlation based user detection may be used in 802.11 UL MUMIMO systems. For example, an access point may detect whether a client station responds to a trigger frame and then adjust a channel matrix accordingly to reflect whether the client station is responsive. The access point may then decode received data signals based on the adjusted channel matrix that reflects whether a client station has transmitted.