Unequal MCS Signaling for SINR-Adaptive Spatial Streams and Frequency Channels

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Solution Overview

Problem

Existing Wi-Fi standards assign a single Modulation and Coding Scheme (MCS) to all spatial streams and frequency channels, leading to compromised data rates due to Signal-Interference-Noise Ratio (SINR) imbalances, and there is a lack of effective methods to indicate unequal MCSs to spatial streams or frequency channels.

Innovation Solution

Implement systems and methods for unequal MCS indication, allowing users to apply unequal MCSs to either spatial streams or frequency channels based on Resource Unit/Multiple Resource Unit (RU/MRU) and spatial streams, with specific restrictions and options for low complexity and overhead, including additional bit indications for high complexity scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single MCS is assigned to all spatial streams and frequency channels, then device complexity is reduced and ease of operation is improved, but data rate is compromised due to SINR imbalances

Engineering Contradiction:
Improvedata rateVSAvoidMCS assignment complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the unified MCS assignment into separate MCS values for different spatial streams and frequency channels. Specifically, it introduces independent MCS parameters for each spatial stream (MCS0, MCS1, ..., MCS(N-1)) and for different frequency channels (primary channel MCS, secondary channel MCS), allowing each segment to be optimized according to its specific SINR conditions while maintaining manageable complexity through structured signaling mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different MCS values to different spatial streams and frequency channels based on their local SINR conditions. Each spatial stream receives an MCS tailored to its specific channel quality, and each frequency channel (primary or secondary) receives an MCS optimized for its local interference and noise characteristics, thereby maximizing overall data rate without requiring uniform complexity across the entire system.

Inventive Principle:
Principle #3Local quality

2Productivity

If unequal MCSs are assigned to different spatial streams or frequency channels, then data rate is improved by adapting to SINR conditions, but signaling overhead and device complexity increase

Engineering Contradiction:
Improvedata rateVSAvoidsignaling overhead
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent extracts the MCS indication information from the general resource allocation framework and places it into dedicated signaling fields within the Downlink Control Information (DCI). By extracting MCS indications for spatial streams and frequency channels into specific, structured fields, the patent reduces overall signaling overhead compared to transmitting complete MCS configurations separately, while still enabling unequal MCS assignment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the MCS indication functionality with the existing resource allocation signaling in the DCI structure. By combining MCS indications for multiple spatial streams and frequency channels into a single integrated signaling message, the patent reduces the total number of separate signaling transmissions required, thereby minimizing signaling overhead while maintaining the capability to assign unequal MCSs.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4645722A1Indication of unequal modulation and coding scheme over spatial streams and frequency channels
Publication Date: 2025.11.05 INTEL CORP
  • EP4645722A1 patent drawingFigure 1
  • EP4645722A1 patent drawingFigure 2
  • EP4645722A1 patent drawingFigure 3

AI summary

This disclosure describes systems, methods, and devices related to unequal MCS indication. A device may extract Resource unit (RU) or multi-RU (M-RU) allocation through one or more fields of a received frame from an associated access point (AP). A device may extract MCS information through MCS subfield of a User field of a User Specific Field in EHT-SIG. The device may extract spatial streams information through a spatial streams subfield of the User field of the User Specific Field in EHT-SIG. The device may determine one or more MCS indications based on the MCS information, RU or MRU allocation, and spatial streams information, determine its MCS indication.