PPDU MCS Group Signaling for Multi-Stream Overhead Reduction

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Solution Overview

Problem

Existing wireless communication standards face challenges in efficiently indicating modulation and coding schemes (MCS) for multiple spatial streams using a small number of bits, leading to increased signaling overheads as the number of spatial streams and MCS types increase.

Innovation Solution

A method and apparatus that utilize a physical layer protocol data unit (PPDU) with specific fields to indicate a modulation and coding scheme group and the number of spatial streams, allowing flexible indication of MCSs across multiple streams with reduced signaling overheads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If one index is used to indicate MCS for each spatial stream individually, then MCS indication precision is improved, but signaling overhead increases exponentially with the number of spatial streams

Engineering Contradiction:

ImproveMCS indication precisionVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the MCS indication into two parts: a first field indicating an MCS group (shared by multiple spatial streams) and a second field indicating the number of spatial streams using each MCS in the group. This segmentation allows precise MCS indication for each stream while reducing overhead by grouping common MCS values.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges the indication of MCS for multiple spatial streams by using a single first field to indicate an MCS group that can be applied to multiple streams, combined with a second field that specifies how many streams use each MCS. This merging reduces redundant signaling compared to individual MCS indication per stream.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If the number of spatial streams and MCS types increases to support more terminals and higher data rates, then system capacity and adaptability are improved, but signaling overhead increases exponentially

Engineering Contradiction:

Improvesystem capacityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent changes the parameter representation by introducing MCS groups instead of individual MCS indices for each stream. The first field indicates an MCS group identifier, and the second field indicates the distribution of spatial streams across MCSs in the group. This parameter change enables support for more spatial streams and MCS types while controlling overhead growth.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4712375A1Modulation and coding scheme indication method and corresponding apparatus

Publication Date: 2026.03.18 HUAWEI TECH CO LTD

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AI summary

Embodiments of this application disclose a modulation and coding scheme indication method and a corresponding apparatus. This application is applied to a wireless local area network system that supports one or more of a next-generation Wi-Fi protocol of IEEE 802.11ax (for example, 802.11be, Wi-Fi 7, or EHT), a next-generation Wi-Fi protocol of IEEE 802.11be (for example, 802.11bn, Wi-Fi 8, or UHR), Wi-Fi AI, a millimeter wave (mmWave), an ultra wideband (UWB), and sensing (sensing). The method includes: generating a physical layer protocol data unit PPDU, where the PPDU includes a first field and a second field, the first field indicates a first modulation and coding scheme MCS group, and the second field indicates a number of spatial streams corresponding to one or more MCSs in the first MCS group; and sending the PPDU. This can reduce bit overheads.