PPDU Preamble Configuration for EHT WLAN Packet Detection

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Solution Overview

Problem

Current wireless local area network (WLAN) systems face challenges in efficiently configuring signal fields, particularly in the extreme high throughput (EHT) standard, which requires new transmission methods and PPDU designs to support high data rates and multiple user operations across different frequency bands.

Innovation Solution

A method for configuring a physical protocol data unit (PPDU) that includes a legacy signal field, a repeated legacy signal field, a first signal field, and a second signal field, where the second signal field is received consecutively and decoded based on specific modulation and constellation mapping to determine the PPDU type and format, enabling rapid identification of the EHT PPDU format and reducing packet detection errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a new PPDU format is introduced for EHT standard, then high throughput and high data rate are achieved, but compatibility with conventional Wi-Fi devices deteriorates

Engineering Contradiction:

ImprovethroughputVSAvoidbackward compatibility

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The PPDU structure is segmented into distinct fields: legacy signal fields (L-SIG, RL-SIG) for backward compatibility, and new signal fields (U-SIG, EHT-SIG) for EHT functionality. This segmentation allows legacy devices to process only the legacy fields while EHT devices can access both legacy and new fields to achieve high throughput.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The repeated legacy signal field (RL-SIG) acts as an intermediary that bridges legacy and new PPDU formats. By repeating the L-SIG field and using specific constellation mappings, the system enables legacy devices to correctly interpret the preamble while EHT devices can identify and process the extended format, thus maintaining compatibility while enabling new functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If signal field configuration is simplified for rapid detection, then packet detection speed is improved, but detection accuracy may deteriorate

Engineering Contradiction:

Improvedetection speedVSAvoidpacket detection accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent uses constellation mapping as a form of 'signal coloring' where different modulation schemes (BPSK, QPSK, etc.) and constellation points encode specific PPDU format information. The receiver can rapidly detect the PPDU type by identifying the constellation pattern, achieving both fast detection and accurate format identification simultaneously.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The signal fields are designed to serve multiple functions: legacy signal fields maintain compatibility with existing devices, while new signal fields (U-SIG, EHT-SIG) provide EHT-specific information. The repeated legacy signal field serves both as a compatibility marker and as a detection mechanism for new PPDU formats, enabling rapid and accurate packet detection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11582076B2Techniques for configuring a preamble in wireless local area network system

Publication Date: 2023.02.14 LG ELECTRONICS INC

AI summary

According to various embodiments, a receiving station (STA) may receive a physical protocol data unit (PPDU). The PPDU may include a legacy signal field, a repeated legacy signal field, a first signal field, and a second signal field. The receiving STA may determine a type of the PPDU and a format of the PPDU, based on the legacy signal field, the repeated legacy signal field, the first signal field, and the second signal field.