20 MHz WLAN RU Allocation Without DC and Guard Tone Loading

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Solution Overview

Problem

Existing wireless LAN systems face challenges in efficiently allocating resources for stations operating in a 20MHz band, leading to potential performance degradation and interference from adjacent channels due to data loading on DC and guard tones.

Innovation Solution

A method and device for allocating resources by limiting RU and MRU specifically for stations operating in a 20MHz band, preventing data loading on DC and guard tones to enhance throughput and reduce interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data is loaded on DC tones and guard tones in a 20MHz band, then resource utilization is improved, but performance degradation and interference from adjacent channels occur

Engineering Contradiction:

Improveresource utilizationVSAvoidperformance stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent extracts and identifies specific tones (DC tones and guard tones) that should be excluded from data loading in 20MHz band operations. By separating these critical tones from the general resource pool, the system prevents data allocation on these tones while maintaining efficient utilization of remaining tones, thus resolving the contradiction between resource utilization and performance stability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different quality rules to different tones within the 20MHz band. Specifically, DC tones and guard tones are designated with restricted data loading properties, while other tones maintain normal data loading capabilities. This localized differentiation ensures that critical tones are protected from interference while maximizing overall resource utilization.

Inventive Principle:

Principle #3Local quality

2Productivity

If data is loaded on DC tones and guard tones in a 20MHz band, then throughput is improved, but interference from adjacent channels increases

Engineering Contradiction:

ImprovethroughputVSAvoidadjacent channel interference

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent recognizes that DC tones and guard tones naturally serve as protective barriers against adjacent channel interference. By explicitly preventing data loading on these tones and maintaining their special status, the system converts what could be wasted resources into active interference protection mechanisms, thus protecting throughput from degradation due to adjacent channel interference.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If RU and MRU allocation is not limited for 20MHz operating STAs, then resource flexibility is improved, but performance degradation occurs

Engineering Contradiction:

Improveresource allocation flexibilityVSAvoidperformance stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic RU and MRU allocation rules that adapt based on the operating bandwidth of STAs. For 20MHz operating STAs, the system dynamically restricts allocations to exclude DC and guard tones, while allowing flexible allocation on other tones. This dynamic approach maintains resource allocation flexibility for legitimate uses while preventing performance degradation through targeted restrictions.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4422344B1Method and device for allocating resource by limiting rus and mrus for sta operating at only 20 mhz in wireless LAN system

Publication Date: 2025.12.24 LG ELECTRONICS INC

Figure 1(a)~1(b)
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AI summary

Proposed are a method and a device for configuring limited RUs and MRUs in a wireless LAN system. Specifically, a receiving STA receives a PPDU from a transmitting STA through a preset frequency band, and decodes the PPDU. The receiving STA is an STA which operates at only a band of 20 MHz. The PPDU includes a preamble and a data field. The data field is received from a resource other than a first RU and a first MRU in the preset frequency band.