Low Power Transmission Preamble Segmentation for WLAN Interference

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Solution Overview

Problem

In high-density wireless local area networks (WLANs), low power transmission devices face interference from legacy devices transmitting at higher power levels, leading to reduced performance and increased contention for channel access, which decreases efficiency and area throughput.

Innovation Solution

Implementing a transmission strategy where a legacy preamble is sent at a high power level, followed by a HEW preamble and payload at a low power level, with the HEW-SIG-A field indicating the power level difference to allow nearby devices to accurately assess channel availability and avoid interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If low power transmission is used, then interference to other devices is reduced, but legacy devices cannot accurately assess channel availability

Engineering Contradiction:

Improveinterference to other devicesVSAvoidchannel availability assessment

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The transmission is segmented into two distinct parts: a legacy preamble transmitted at high power level and a HEW payload transmitted at low power level. This segmentation allows legacy devices to accurately detect the high-power preamble for channel assessment while the low-power payload causes minimal interference to other devices.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the transmission have different power characteristics. The legacy preamble portion is transmitted at high power to ensure legacy devices can detect it for channel availability assessment, while the HEW payload portion is transmitted at low power to reduce interference to other devices operating in the vicinity.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If high power transmission is used, then channel availability detection is accurate, but interference to other devices increases

Engineering Contradiction:

Improvechannel availability assessmentVSAvoidinterference to other devices

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The transmission is divided into a high-power legacy preamble segment for accurate channel detection and a low-power HEW payload segment that minimizes interference to other devices.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The legacy preamble portion uses high power transmission to ensure accurate detection by legacy devices, while the HEW payload portion uses low power transmission to reduce harmful interference to other devices in the vicinity.

Inventive Principle:

Principle #3Local quality

3Device complexity

If uniform power level transmission is used, then implementation is simple, but cell splitting gain is reduced

Engineering Contradiction:

Improvetransmission implementationVSAvoidcell splitting gain

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The transmission power level is dynamically adjusted based on the portion of the transmission being sent. The legacy preamble is transmitted at a first power level while the HEW payload is transmitted at a second, lower power level, enabling cell splitting gain without significantly increasing implementation complexity.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3236691B1System and method for low power transmission

Publication Date: 2019.06.26 HUAWEI TECH CO LTD

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AI summary

A method for operating a transmitting device includes generating a frame having a first preamble and a second preamble (block 605). The method also includes transmitting a first preamble at a first power level (block 615), and transmitting a subset of a second preamble at a second power level (block 625), wherein the first power level and the second power level differ.