Wireless Signaling Distortion Threshold for MU-MIMO Feedback
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Solution Overview
Problem
Current wireless communication networks face inefficiencies in channel feedback mechanisms, particularly in MU-MIMO transmissions, due to unnecessary feedback from stable channels and increased feedback delay, which can lead to residual interference and reduced airtime for data transmission.
Innovation Solution
Implementing a signaling method that uses a distortion threshold to selectively request channel feedback only from wireless terminal devices with significant channel changes, employing a ZC-sequence detection algorithm to identify qualifying devices and reduce feedback overhead, thereby improving channel feedback efficiency and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel feedback is requested from all wireless terminal devices in MU-MIMO transmissions, then channel estimation accuracy is improved, but feedback overhead and airtime consumption increase
Solution Approach 1:
The patent changes the parameter of feedback selection from all devices to only those with significant channel changes. It introduces a distortion threshold parameter to quantify channel change magnitude, and uses this parameter to dynamically determine which devices should provide feedback, thereby reducing feedback overhead while maintaining necessary estimation accuracy
Solution Approach 2:
Instead of requesting feedback from all wireless terminal devices (excessive action), the patent requests feedback only from a subset of devices whose channel estimates have changed beyond a threshold (partial action). This partial feedback approach is sufficient to maintain channel estimation accuracy for MU-MIMO transmissions without the overhead of universal feedback
2Measurement precision
If channel feedback is requested frequently to track channel changes, then channel estimation accuracy is improved, but feedback delay and airtime for data transmission increase
Solution Approach 1:
The patent implements a feedback mechanism where wireless terminal devices compare their current channel estimates with previous ones and provide feedback only when the distortion exceeds a threshold. This selective feedback approach ensures that the access point receives timely updates only when necessary, maintaining channel estimation accuracy while minimizing feedback delay and preserving airtime for data transmission
Solution Approach 2:
The patent employs periodic channel estimation at wireless terminal devices, where devices periodically compare current channel estimates with previous ones. However, feedback is transmitted only periodically when needed (when distortion exceeds threshold), rather than continuously, thus reducing feedback delay and airtime consumption while maintaining estimation accuracy
3Reliability
If channel feedback is requested from all devices, then channel estimation reliability is improved, but airtime availability for data transmission decreases
Solution Approach 1:
The patent requests feedback only from a partial subset of wireless terminal devices—specifically those experiencing significant channel changes beyond a distortion threshold—rather than from all devices. This partial feedback approach maintains sufficient channel estimation reliability for MU-MIMO transmissions while preserving airtime availability for data transmission by eliminating redundant feedback requests from devices with stable channels
Data Source
AI summary
Embodiments of the invention provide signaling mechanisms for wireless networks composed of a large number of stations. An example method embodiment comprises: storing, by a wireless device, a prior channel estimate that was previously transmitted to another wireless device in a wireless network; receiving, by the wireless device, a request message from the other device, to determine a distortion between a current channel estimate and the prior channel estimate and compare the determined distortion to a distortion threshold value, the request message being a broadcast request message or a measurement request message and the distortion value being either included in the request message, received in another message, or a preconfigured value; determining, by the wireless device, the distortion between the current channel estimate and the prior channel estimate and comparing the determined distortion to the distortion threshold value; and transmitting, by the wireless device, one or more parallel or sequential messages to the other device, indicating presence of the determined distortion greater than the distortion threshold value or indicating an inability to determine a distortion in channel estimates.