MCS Feedback Responder for WLAN Link Adaptation
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Solution Overview
Problem
In Wireless Local Area Networks (WLAN) systems, particularly in Very High Throughput (VHT) WLANs, determining an optimal Modulation and Coding Scheme (MCS) for data transmission is challenging due to varying channel environments and the need for efficient feedback mechanisms that account for multiple spatial streams and diverse channel conditions, while maintaining backward compatibility.
Innovation Solution
A method where a Modulation and Coding Scheme (MCS) feedback responder derives and sends a recommended MCS value based on unsolicit type information, transmission type, coding scheme, group ID, and channel bandwidth information, implicitly transmitted through the Physical Layer Convergence Procedure (PLCP) preamble, allowing the MCS requester to determine the optimal MCS for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple spatial streams and diverse channel conditions are used to improve data throughput in VHT WLAN systems, then the data processing speed increases, but the complexity of determining optimal MCS values increases
Solution Approach 1:
The patent segments the MCS determination process by introducing a feedback mechanism where the receiver independently evaluates channel conditions for each spatial stream and provides feedback information to the transmitter. This divides the complex joint optimization problem into separate per-stream evaluations, making the system manageable while supporting multiple spatial streams for high throughput.
Solution Approach 2:
The patent implements a feedback loop where the receiver measures channel conditions, determines appropriate MCS values for each spatial stream, and sends feedback information back to the transmitter. This enables adaptive MCS selection that accounts for diverse channel conditions across multiple streams without requiring the transmitter to directly compute optimal values for all streams simultaneously.
2Productivity
If implicit transmission through PLCP preamble is used to reduce overhead, then the feedback efficiency improves, but the amount of information that can be transmitted is limited
Solution Approach 1:
The patent extracts only the essential feedback information needed for MCS determination and transmits it implicitly through the PLCP preamble. By taking out only the critical parameters (such as recommended MCS values or channel quality indicators) rather than transmitting complete channel state information, the system achieves efficient feedback with minimal overhead while providing sufficient information for optimal MCS selection.
Data Source
AI summary
The present invention relates to a method of determining a Modulation and Coding Scheme (MCS) feedback in a Wireless Local Area Network (WLAN) system, including an MCS FeedBack (MFB) responder receiving a first frame, including a request message requesting to send the MFB, from an MFB requester and the MFB responder sending the MFB, including a recommended MCS value, to the MFB requester. The recommended MCS value is derived with reference to at least one of unsolicit type information indicative of a type of the MFB, transmit type information indicative of a transmission type of data, coding type information indicative of a coding scheme applied to the data, a group ID indicative of a group of target stations (STAs) to which the data will be transmitted, and MFB bandwidth information indicative of a bandwidth of a channel.